diff --git a/decnet/config.py b/decnet/config.py
index c4913ffc..4bcda23f 100644
--- a/decnet/config.py
+++ b/decnet/config.py
@@ -79,9 +79,12 @@ def _configure_logging(dev: bool) -> None:
     stream_handler.setFormatter(fmt)
     root.addHandler(stream_handler)
 
-    # Skip the file handler during pytest runs to avoid polluting the test cwd.
-    _in_pytest = any(k.startswith("PYTEST") for k in os.environ)
-    if not _in_pytest:
+    # Skip the file handler during test runs to avoid polluting the test cwd.
+    # Gated on the explicit, non-attacker-injectable DECNET_TESTING=1 flag
+    # (set by the test harness) rather than the attacker-controllable PYTEST*
+    # namespace (V2.1.7).
+    _in_test = os.environ.get("DECNET_TESTING") == "1"
+    if not _in_test:
         _log_path = os.environ.get("DECNET_SYSTEM_LOGS", "decnet.system.log")
         # Never let file-handler attach failure kill the process. The
         # stream handler above is already installed, so losing the file
diff --git a/decnet/env.py b/decnet/env.py
index fc0c3e3f..9880a109 100644
--- a/decnet/env.py
+++ b/decnet/env.py
@@ -58,8 +58,10 @@ def _require_env(name: str) -> str:
         return value
 
     if value.lower() in _KNOWN_BAD:
+        # Do NOT echo the rejected value — that leaks the secret into logs /
+        # stderr / crash reporters (V7.1.3). Name the variable, not its value.
         raise ValueError(
-            f"Environment variable '{name}' is set to an insecure default ('{value}'). "
+            f"Environment variable '{name}' is set to a known-insecure default. "
             f"Choose a strong, unique value before starting DECNET."
         )
     _developer = os.environ.get("DECNET_DEVELOPER", "False").lower() == "true"
@@ -275,10 +277,14 @@ def validate_public_binding() -> None:
       slip past unmentioned on a public binding.
 
     Called from the FastAPI lifespan so it surfaces at startup, not on
-    first request. Skipped automatically when running under pytest so
-    the test suite doesn't have to set five env vars per fixture.
+    first request. Skipped automatically under the explicit, non-attacker-
+    injectable DECNET_TESTING=1 flag (set by the test harness) so the test
+    suite doesn't have to set five env vars per fixture. The old "any PYTEST*
+    var present" check was fail-open: PYTEST* is an attacker-controllable
+    namespace, so leaking one into a prod environment silently disabled the
+    public-binding guard. Fail closed (V2.1.7).
     """
-    if any(k.startswith("PYTEST") for k in os.environ):
+    if os.environ.get("DECNET_TESTING") == "1":
         return
     if DECNET_API_HOST in _LOOPBACK_HOSTS:
         return  # not exposed; nothing to validate
diff --git a/decnet/swarm/log_forwarder.py b/decnet/swarm/log_forwarder.py
index 9fa95a13..2b8a3d07 100644
--- a/decnet/swarm/log_forwarder.py
+++ b/decnet/swarm/log_forwarder.py
@@ -108,6 +108,9 @@ def build_worker_ssl_context(agent_dir: pathlib.Path) -> ssl.SSLContext:
             f"no worker bundle at {agent_dir} — enroll from the master first"
         )
     ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
+    # Pin an explicit TLS 1.2 floor so it can't silently regress if a future
+    # runtime lowers the implicit default (ASVS V9.1.4).
+    ctx.minimum_version = ssl.TLSVersion.TLSv1_2
     ctx.load_cert_chain(
         certfile=str(agent_dir / "worker.crt"),
         keyfile=str(agent_dir / "worker.key"),
diff --git a/decnet/swarm/log_listener.py b/decnet/swarm/log_listener.py
index 6769e473..a727a915 100644
--- a/decnet/swarm/log_listener.py
+++ b/decnet/swarm/log_listener.py
@@ -61,6 +61,9 @@ def build_listener_ssl_context(ca_dir: pathlib.Path) -> ssl.SSLContext:
                 f"master identity missing at {master_dir} — call ensure_master_identity first"
             )
     ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
+    # Pin an explicit TLS 1.2 floor so it can't silently regress if a future
+    # runtime lowers the implicit default (ASVS V9.1.4).
+    ctx.minimum_version = ssl.TLSVersion.TLSv1_2
     ctx.load_cert_chain(certfile=str(cert), keyfile=str(key))
     ctx.load_verify_locations(cafile=str(ca_cert))
     ctx.verify_mode = ssl.CERT_REQUIRED
diff --git a/decnet/updater/app.py b/decnet/updater/app.py
index c14a8c34..007981b1 100644
--- a/decnet/updater/app.py
+++ b/decnet/updater/app.py
@@ -165,8 +165,8 @@ async def update(
     try:
         return _exec.run_update(
             body, sha=sha or None,
+            expected_sha256=sha256,
             install_dir=_Config.install_dir, agent_dir=_Config.agent_dir,
-            expected_sha256=sha256 or None,
         )
     except _exec.UpdateError as exc:
         status = 409 if exc.rolled_back else 500
@@ -196,7 +196,7 @@ async def update_self(
         return _exec.run_update_self(
             body, sha=sha or None,
             updater_install_dir=_Config.updater_install_dir,
-            expected_sha256=sha256 or None,
+            expected_sha256=sha256,
         )
     except _exec.UpdateError as exc:
         raise HTTPException(
diff --git a/decnet/updater/executor.py b/decnet/updater/executor.py
index b319bece..0576b658 100644
--- a/decnet/updater/executor.py
+++ b/decnet/updater/executor.py
@@ -576,19 +576,22 @@ def _point_current_at(install_dir: pathlib.Path, target: pathlib.Path) -> None:
     os.replace(tmp, link)
 
 
-def _verify_tarball_sha256(tarball_bytes: bytes, expected_sha256: Optional[str]) -> None:
+def _verify_tarball_sha256(tarball_bytes: bytes, expected_sha256: str) -> None:
     """Refuse to extract a tarball whose SHA-256 disagrees with the operator-supplied digest.
 
     mTLS already authenticates the master, so a network MITM can't forge
-    bytes. This check exists for two narrower cases: catching corruption
+    bytes. This check is mandatory defense-in-depth: it catches corruption
     in transit (proxies, broken disks) before we explode a half-decoded
-    archive into the staging tree, and giving the operator a way to pin
-    "exactly these bytes" when distributing a vetted release. The form
-    field is optional — if the caller doesn't send one, we skip the
-    check rather than reject (no breaking change for older masters).
+    archive into the staging tree, and pins "exactly these bytes" when
+    distributing a vetted release. It runs BEFORE extraction or any
+    pip-install. There is no skip path: a missing/empty digest is a
+    fail-closed REJECT — every caller (UpdaterClient) computes and sends
+    the digest, so an absent one means an untrusted/malformed request.
     """
-    if not expected_sha256:
-        return
+    if not expected_sha256 or not expected_sha256.strip():
+        raise UpdateError(
+            "tarball sha256 digest is required but was missing or empty — refusing to extract"
+        )
     expected = expected_sha256.strip().lower()
     if len(expected) != 64 or any(c not in "0123456789abcdef" for c in expected):
         raise UpdateError(f"sha256 digest is not a 64-char hex string: {expected_sha256!r}")
@@ -602,9 +605,9 @@ def _verify_tarball_sha256(tarball_bytes: bytes, expected_sha256: Optional[str])
 def run_update(
     tarball_bytes: bytes,
     sha: Optional[str],
+    expected_sha256: str,
     install_dir: pathlib.Path = DEFAULT_INSTALL_DIR,
     agent_dir: pathlib.Path = pki.DEFAULT_AGENT_DIR,
-    expected_sha256: Optional[str] = None,
 ) -> dict[str, Any]:
     """Apply an update atomically. Rolls back on probe failure."""
     log.info("update received sha=%s bytes=%d install_dir=%s", sha, len(tarball_bytes), install_dir)
@@ -699,8 +702,8 @@ def run_update_self(
     tarball_bytes: bytes,
     sha: Optional[str],
     updater_install_dir: pathlib.Path,
+    expected_sha256: str,
     exec_cb: Optional[Callable[[list[str]], None]] = None,
-    expected_sha256: Optional[str] = None,
 ) -> dict[str, Any]:
     """Replace the updater's own source tree, then re-exec this process.
 
diff --git a/decnet/web/api.py b/decnet/web/api.py
index b362561c..73960502 100644
--- a/decnet/web/api.py
+++ b/decnet/web/api.py
@@ -15,6 +15,8 @@ from fastapi.exceptions import RequestValidationError
 from fastapi.responses import ORJSONResponse, Response
 from pydantic import ValidationError
 from fastapi.middleware.cors import CORSMiddleware
+from starlette.middleware.base import BaseHTTPMiddleware
+from starlette.responses import Response as StarletteResponse
 
 from decnet.env import (
     DECNET_CORS_ORIGINS,
@@ -59,6 +61,20 @@ def get_background_tasks() -> dict[str, Optional[asyncio.Task[Any]]]:
     }
 
 
+def _check_cors_origins(origins: list[str]) -> None:
+    """V13.1.4 — raise at startup if a wildcard CORS origin is configured.
+
+    Called from the lifespan so the error surfaces before any worker or DB
+    comes up, making misconfiguration immediately visible in uvicorn logs.
+    Exposed as a module-level function so tests can exercise it directly
+    without needing to reload the module.
+    """
+    if "*" in origins:
+        raise ValueError(
+            "DECNET_CORS_ORIGINS must not contain a wildcard '*' — list explicit origin URLs"
+        )
+
+
 @asynccontextmanager
 async def lifespan(app: FastAPI) -> AsyncGenerator[None, None]:
     global ingestion_task, collector_task, attacker_task, sniffer_task
@@ -79,6 +95,10 @@ async def lifespan(app: FastAPI) -> AsyncGenerator[None, None]:
     # Raises ValueError with an actionable message; uvicorn surfaces it.
     validate_public_binding()
 
+    # V13.1.4 — CORS wildcard guard: wildcard '*' bypasses SOP and must be
+    # rejected at startup so the operator sees an actionable error immediately.
+    _check_cors_origins(DECNET_CORS_ORIGINS)
+
     # Defence-in-depth on top of the CLI mode gating. Typer hides master-only
     # commands when DECNET_MODE=agent, but a misconfigured systemd unit or
     # a direct `python -m uvicorn decnet.web.api:app` call would bypass that.
@@ -254,6 +274,43 @@ app.add_middleware(
     allow_headers=["Authorization", "Content-Type", "Last-Event-ID"],
 )
 
+# V13.1.5 — Content-Type enforcement: POST/PUT/PATCH with a non-empty body
+# under /api/ must send application/json.  Multipart/form-data endpoints
+# (file-drop, canary blob upload) are exempt by their Content-Type prefix.
+_MULTIPART_EXEMPT_PATHS: frozenset[str] = frozenset({
+    "/api/v1/deckies/files",
+    "/api/v1/canary/blobs",
+})
+_JSON_ENFORCE_METHODS: frozenset[str] = frozenset({"POST", "PUT", "PATCH"})
+
+
+class _ContentTypeMiddleware(BaseHTTPMiddleware):
+    async def dispatch(self, request: Request, call_next: Any) -> StarletteResponse:
+        if (
+            request.method in _JSON_ENFORCE_METHODS
+            and request.url.path.startswith("/api/")
+        ):
+            # Allow through if the path belongs to a multipart-exempt route.
+            path = request.url.path
+            exempt = any(path.startswith(p) for p in _MULTIPART_EXEMPT_PATHS)
+            if not exempt:
+                ct = request.headers.get("content-type", "")
+                # Only enforce when a body is actually present (non-zero Content-Length
+                # or chunked transfer), so empty-body POST health-checks stay clean.
+                cl = request.headers.get("content-length", "")
+                te = request.headers.get("transfer-encoding", "")
+                has_body = (cl not in ("", "0")) or ("chunked" in te.lower())
+                if has_body and not ct.lower().startswith("application/json"):
+                    return StarletteResponse(
+                        content="Unsupported Media Type — Content-Type must be application/json",
+                        status_code=415,
+                        media_type="text/plain",
+                    )
+        return await call_next(request)
+
+
+app.add_middleware(_ContentTypeMiddleware)
+
 if DECNET_PROFILE_REQUESTS:
     import time
     from pathlib import Path
diff --git a/decnet/web/db/mysql/database.py b/decnet/web/db/mysql/database.py
index d52fb35c..7caac4da 100644
--- a/decnet/web/db/mysql/database.py
+++ b/decnet/web/db/mysql/database.py
@@ -50,12 +50,14 @@ def build_mysql_url(
     if password is None:
         password = os.environ.get("DECNET_DB_PASSWORD") or ""
 
-    # Allow empty passwords during tests (pytest sets PYTEST_* env vars).
-    # Outside tests, an empty MySQL password is almost never intentional.
-    if not password and not any(k.startswith("PYTEST") for k in os.environ):
+    # Allow empty passwords during tests, gated on the explicit, non-attacker-
+    # injectable DECNET_TESTING=1 flag (set by the test harness) rather than
+    # the attacker-controllable PYTEST* namespace (V2.1.7). Outside tests, an
+    # empty MySQL password is almost never intentional.
+    if not password and os.environ.get("DECNET_TESTING") != "1":
         raise ValueError(
             "DECNET_DB_PASSWORD is not set. Either export it, set DECNET_DB_URL, "
-            "or run under pytest for an empty-password default."
+            "or run under the test harness (DECNET_TESTING=1) for an empty-password default."
         )
 
     pw_enc = quote_plus(password)
diff --git a/decnet/web/router/stream/api_stream_events.py b/decnet/web/router/stream/api_stream_events.py
index 19c8c715..a00416c1 100644
--- a/decnet/web/router/stream/api_stream_events.py
+++ b/decnet/web/router/stream/api_stream_events.py
@@ -139,7 +139,7 @@ async def stream_events(
             except asyncio.CancelledError:
                 pass
             except Exception:
-                log.exception("SSE stream error for user %s", last_event_id)
+                log.exception("SSE stream error for user %s", user["uuid"])
                 yield f"event: error\ndata: {orjson.dumps({'type': 'error', 'message': 'Stream interrupted'}).decode()}\n\n"
 
     return StreamingResponse(
diff --git a/tests/api/test_security_middleware.py b/tests/api/test_security_middleware.py
new file mode 100644
index 00000000..cc454c89
--- /dev/null
+++ b/tests/api/test_security_middleware.py
@@ -0,0 +1,204 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""
+Security-middleware tests covering:
+  - V13.1.4: CORS wildcard guard raises ValueError at app startup
+  - V13.1.5: Content-Type enforcement middleware (415 on wrong CT; pass for
+             application/json; multipart exempt paths; GET/DELETE unaffected)
+  - BUG-17:  SSE stream error log uses user["uuid"], not last_event_id
+  - Regression: multipart upload endpoints still work (canary blob, file-drop)
+"""
+from __future__ import annotations
+
+import pytest
+import httpx
+
+
+# ---------------------------------------------------------------------------
+# V13.1.4 — CORS wildcard guard (unit tests; lifespan path in tests/web/)
+# ---------------------------------------------------------------------------
+
+class TestCORSWildcardGuard:
+    def test_wildcard_raises(self):
+        """_check_cors_origins raises ValueError when '*' is present."""
+        from decnet.web.api import _check_cors_origins
+        with pytest.raises(ValueError, match="wildcard"):
+            _check_cors_origins(["*"])
+
+    def test_wildcard_among_explicit_origins_raises(self):
+        """Wildcard in a mixed list is still rejected."""
+        from decnet.web.api import _check_cors_origins
+        with pytest.raises(ValueError, match="wildcard"):
+            _check_cors_origins(["https://example.com", "*"])
+
+    def test_explicit_origins_ok(self):
+        """Explicit origin URLs pass without raising."""
+        from decnet.web.api import _check_cors_origins
+        _check_cors_origins(["https://example.com", "https://app.internal"])
+
+    def test_empty_origins_ok(self):
+        """Empty list is valid (no CORS)."""
+        from decnet.web.api import _check_cors_origins
+        _check_cors_origins([])
+
+
+# ---------------------------------------------------------------------------
+# V13.1.5 — Content-Type enforcement middleware
+# ---------------------------------------------------------------------------
+
+class TestContentTypeMiddleware:
+    @pytest.mark.asyncio
+    async def test_post_wrong_content_type_returns_415(
+        self, client: httpx.AsyncClient
+    ):
+        """POST with text/plain body to a JSON endpoint returns 415.
+
+        /api/v1/auth/login is the most stable JSON POST target — no auth
+        required, always present, middleware fires before the handler.
+        """
+        resp = await client.post(
+            "/api/v1/auth/login",
+            content=b"not json",
+            headers={"Content-Type": "text/plain"},
+        )
+        assert resp.status_code == 415
+
+    @pytest.mark.asyncio
+    async def test_post_application_json_passes_middleware(
+        self, client: httpx.AsyncClient
+    ):
+        """POST with application/json does NOT get a 415 from middleware."""
+        resp = await client.post(
+            "/api/v1/auth/login",
+            json={"username": "nobody", "password": "wrong"},
+        )
+        # Middleware passes; handler may 401/422 but must not 415.
+        assert resp.status_code != 415
+
+    @pytest.mark.asyncio
+    async def test_post_json_with_charset_passes(
+        self, client: httpx.AsyncClient
+    ):
+        """application/json; charset=utf-8 is a valid Content-Type."""
+        resp = await client.post(
+            "/api/v1/auth/login",
+            content=b'{"username":"x","password":"y"}',
+            headers={"Content-Type": "application/json; charset=utf-8"},
+        )
+        assert resp.status_code != 415
+
+    @pytest.mark.asyncio
+    async def test_get_not_enforced(self, client: httpx.AsyncClient, auth_token: str):
+        """GET requests are never rejected by the CT middleware."""
+        resp = await client.get(
+            "/api/v1/logs",
+            headers={"Authorization": f"Bearer {auth_token}"},
+        )
+        assert resp.status_code != 415
+
+    @pytest.mark.asyncio
+    async def test_delete_not_enforced(
+        self, client: httpx.AsyncClient, auth_token: str
+    ):
+        """DELETE requests are never rejected by the CT middleware."""
+        resp = await client.delete(
+            "/api/v1/deckies/nonexistent",
+            headers={"Authorization": f"Bearer {auth_token}"},
+        )
+        # Could be 404/401/403 but never 415.
+        assert resp.status_code != 415
+
+    @pytest.mark.asyncio
+    async def test_multipart_canary_blob_exempt(
+        self, client: httpx.AsyncClient, auth_token: str
+    ):
+        """Canary blob upload (multipart/form-data) is NOT rejected with 415."""
+        resp = await client.post(
+            "/api/v1/canary/blobs",
+            files={"file": ("test.txt", b"hello world", "text/plain")},
+            headers={"Authorization": f"Bearer {auth_token}"},
+        )
+        # 201 on success, 4xx on business-logic errors — never 415.
+        assert resp.status_code != 415
+
+    @pytest.mark.asyncio
+    async def test_multipart_file_drop_exempt(
+        self, client: httpx.AsyncClient, auth_token: str
+    ):
+        """Decky file-drop (multipart/form-data) is NOT rejected with 415."""
+        resp = await client.post(
+            "/api/v1/deckies/files/some-container",
+            files={"file": ("test.txt", b"data", "text/plain")},
+            headers={"Authorization": f"Bearer {auth_token}"},
+        )
+        # Expect 4xx business error (no real container), never 415.
+        assert resp.status_code != 415
+
+    @pytest.mark.asyncio
+    async def test_empty_body_post_not_enforced(
+        self, client: httpx.AsyncClient, auth_token: str
+    ):
+        """POST with genuinely empty body (Content-Length: 0) is not rejected."""
+        resp = await client.post(
+            "/api/v1/logs",
+            content=b"",
+            headers={
+                "Authorization": f"Bearer {auth_token}",
+                "Content-Length": "0",
+            },
+        )
+        # Middleware should not 415 on empty bodies.
+        assert resp.status_code != 415
+
+
+# ---------------------------------------------------------------------------
+# BUG-17 — SSE error log uses user["uuid"], not last_event_id
+# ---------------------------------------------------------------------------
+
+class TestSSEErrorLog:
+    def test_sse_error_log_uses_user_uuid(self):
+        """
+        Verify the log.exception call in the SSE generator uses user["uuid"],
+        not last_event_id (which is an int cursor, not an identity).
+        """
+        import ast, pathlib
+        src = pathlib.Path(
+            "decnet/web/router/stream/api_stream_events.py"
+        ).read_text()
+        tree = ast.parse(src)
+
+        bad_pattern_found = False
+        correct_pattern_found = False
+
+        for node in ast.walk(tree):
+            if not isinstance(node, ast.Call):
+                continue
+            # Look for log.exception(...) calls
+            func = node.func
+            if not (isinstance(func, ast.Attribute) and func.attr == "exception"):
+                continue
+            # Check args after the format string
+            if len(node.args) >= 2:
+                arg = node.args[1]
+                # Bad pattern: bare Name "last_event_id"
+                if isinstance(arg, ast.Name) and arg.id == "last_event_id":
+                    bad_pattern_found = True
+                # Good pattern: user["uuid"] subscript
+                if (
+                    isinstance(arg, ast.Subscript)
+                    and isinstance(arg.value, ast.Name)
+                    and arg.value.id == "user"
+                ):
+                    correct_pattern_found = True
+
+        assert not bad_pattern_found, (
+            "BUG-17: log.exception still uses last_event_id instead of user['uuid']"
+        )
+        assert correct_pattern_found, (
+            "BUG-17 fix not found: expected log.exception(..., user['uuid']) in SSE handler"
+        )
+
+    @pytest.mark.asyncio
+    async def test_sse_stream_unauthenticated_401(self, client: httpx.AsyncClient):
+        """SSE endpoint rejects unauthenticated requests (regression guard)."""
+        resp = await client.get("/api/v1/stream")
+        assert resp.status_code == 401
diff --git a/tests/core/test_env_secrets.py b/tests/core/test_env_secrets.py
index b12fd799..a5184f32 100644
--- a/tests/core/test_env_secrets.py
+++ b/tests/core/test_env_secrets.py
@@ -4,7 +4,7 @@
 DECNET_ADMIN_PASSWORD must never silently default to "admin": it is resolved
 lazily and validated like DECNET_JWT_SECRET. These tests drive _require_env
 against a controlled environ so the production raise paths (which are bypassed
-under live pytest) are actually exercised.
+under the test harness via DECNET_TESTING=1) are actually exercised.
 """
 from __future__ import annotations
 
@@ -14,8 +14,8 @@ import decnet.env as envmod
 
 
 def _require(monkeypatch: pytest.MonkeyPatch, environ: dict[str, str]) -> str:
-    # Replace the whole environ for the call so the PYTEST_* short-circuit in
-    # _require_env doesn't fire — we want the real production behaviour.
+    # Replace the whole environ for the call so the DECNET_TESTING short-circuit
+    # in _require_env doesn't fire — we want the real production behaviour.
     monkeypatch.setattr(envmod.os, "environ", dict(environ))
     return envmod._require_env("DECNET_ADMIN_PASSWORD")
 
@@ -36,6 +36,20 @@ def test_admin_password_other_known_bad_raises(monkeypatch: pytest.MonkeyPatch,
         _require(monkeypatch, {"DECNET_ADMIN_PASSWORD": bad})
 
 
+def test_known_bad_message_does_not_leak_secret_value(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    # V7.1.3: the known-bad rejection must NOT echo the rejected secret value
+    # (it would land in logs / stderr / crash reporters). Name the variable,
+    # not its value.
+    secret = "admin"
+    with pytest.raises(ValueError) as exc:
+        _require(monkeypatch, {"DECNET_ADMIN_PASSWORD": secret})
+    msg = str(exc.value)
+    assert secret not in msg
+    assert "DECNET_ADMIN_PASSWORD" in msg
+
+
 def test_admin_password_too_short_raises_in_production(monkeypatch: pytest.MonkeyPatch) -> None:
     with pytest.raises(ValueError, match="too short"):
         _require(monkeypatch, {"DECNET_ADMIN_PASSWORD": "short1"})
diff --git a/tests/db/mysql/test_mysql_url_builder.py b/tests/db/mysql/test_mysql_url_builder.py
index daa09bb2..b44a4710 100644
--- a/tests/db/mysql/test_mysql_url_builder.py
+++ b/tests/db/mysql/test_mysql_url_builder.py
@@ -13,7 +13,7 @@ def test_build_url_defaults(monkeypatch):
     for v in ("DECNET_DB_HOST", "DECNET_DB_PORT", "DECNET_DB_NAME",
               "DECNET_DB_USER", "DECNET_DB_PASSWORD", "DECNET_DB_URL"):
         monkeypatch.delenv(v, raising=False)
-    # PYTEST_* is set by pytest itself, so empty password is allowed here.
+    # DECNET_TESTING=1 is set by conftest, so empty password is allowed here.
     url = build_mysql_url()
     assert url == "mysql+asyncmy://decnet:@localhost:3306/decnet"
 
@@ -66,14 +66,13 @@ def test_resolve_url_falls_back_to_components(monkeypatch):
     assert url.startswith("mysql+asyncmy://")
 
 
-def test_build_url_requires_password_outside_pytest(monkeypatch):
-    """Without a password and not in a pytest run, construction must fail loudly."""
+def test_build_url_requires_password_outside_tests(monkeypatch):
+    """Without a password and not under the test harness, construction must fail loudly."""
     for v in ("DECNET_DB_URL", "DECNET_DB_PASSWORD"):
         monkeypatch.delenv(v, raising=False)
-    # Strip every PYTEST_* env var so the safety check trips.
-    import os
-    for k in list(os.environ):
-        if k.startswith("PYTEST"):
-            monkeypatch.delenv(k, raising=False)
+    # Clear the test-harness flag so the safety check trips. A leaked PYTEST_*
+    # var must NOT re-enable the bypass (V2.1.7).
+    monkeypatch.delenv("DECNET_TESTING", raising=False)
+    monkeypatch.setenv("PYTEST_CURRENT_TEST", "x")
     with pytest.raises(ValueError, match="DECNET_DB_PASSWORD is not set"):
         build_mysql_url()
diff --git a/tests/swarm/test_forwarder_resilience.py b/tests/swarm/test_forwarder_resilience.py
index 2c90d2df..7456060f 100644
--- a/tests/swarm/test_forwarder_resilience.py
+++ b/tests/swarm/test_forwarder_resilience.py
@@ -69,6 +69,18 @@ async def _wait_for(pred, timeout: float = 5.0, interval: float = 0.1) -> bool:
 # ----------------------------------------------------------- pure helpers
 
 
+def test_worker_ssl_context_pins_tls12_floor(_pki_env: dict) -> None:
+    """V9.1.4: forwarder client context must set an explicit TLS 1.2 floor."""
+    ctx = fwd.build_worker_ssl_context(_pki_env["worker_dir"])
+    assert ctx.minimum_version == ssl.TLSVersion.TLSv1_2
+
+
+def test_listener_ssl_context_pins_tls12_floor(_pki_env: dict) -> None:
+    """V9.1.4: listener server context must set an explicit TLS 1.2 floor."""
+    ctx = lst.build_listener_ssl_context(_pki_env["ca_dir"])
+    assert ctx.minimum_version == ssl.TLSVersion.TLSv1_2
+
+
 def test_peer_cn_returns_unknown_when_no_ssl_object() -> None:
     assert lst.peer_cn(None) == "unknown"
 
diff --git a/tests/updater/test_updater_app.py b/tests/updater/test_updater_app.py
index 33088dd9..1c9c1e4f 100644
--- a/tests/updater/test_updater_app.py
+++ b/tests/updater/test_updater_app.py
@@ -54,10 +54,13 @@ def test_health_returns_role_and_releases(client: TestClient, monkeypatch: pytes
 
 
 def test_update_happy_path(client: TestClient, monkeypatch: pytest.MonkeyPatch) -> None:
-    monkeypatch.setattr(
-        ex, "run_update",
-        lambda data, sha, install_dir, agent_dir, expected_sha256=None: {"status": "updated", "release": {"slot": "active", "sha": sha}, "probe": "ok"},
-    )
+    seen: dict[str, object] = {}
+
+    def _run_update(data, sha, expected_sha256, install_dir, agent_dir):
+        seen["expected_sha256"] = expected_sha256
+        return {"status": "updated", "release": {"slot": "active", "sha": sha}, "probe": "ok"}
+
+    monkeypatch.setattr(ex, "run_update", _run_update)
     r = client.post(
         "/update",
         files={"tarball": ("tree.tgz", _tarball(), "application/gzip")},
@@ -65,6 +68,8 @@ def test_update_happy_path(client: TestClient, monkeypatch: pytest.MonkeyPatch)
     )
     assert r.status_code == 200, r.text
     assert r.json()["release"]["sha"] == "ABC123"
+    # Route forwards the digest verbatim — executor verifies it before extract.
+    assert seen["expected_sha256"] == "0" * 64
 
 
 def test_update_rollback_returns_409(client: TestClient, monkeypatch: pytest.MonkeyPatch) -> None:
@@ -104,10 +109,13 @@ def test_update_self_requires_confirm(client: TestClient) -> None:
 
 
 def test_update_self_happy_path(client: TestClient, monkeypatch: pytest.MonkeyPatch) -> None:
-    monkeypatch.setattr(
-        ex, "run_update_self",
-        lambda data, sha, updater_install_dir, expected_sha256=None: {"status": "self_update_queued", "argv": ["python", "-m", "decnet", "updater"]},
-    )
+    seen: dict[str, object] = {}
+
+    def _run_update_self(data, sha, updater_install_dir, expected_sha256):
+        seen["expected_sha256"] = expected_sha256
+        return {"status": "self_update_queued", "argv": ["python", "-m", "decnet", "updater"]}
+
+    monkeypatch.setattr(ex, "run_update_self", _run_update_self)
     r = client.post(
         "/update-self",
         files={"tarball": ("t.tgz", _tarball(), "application/gzip")},
@@ -115,6 +123,7 @@ def test_update_self_happy_path(client: TestClient, monkeypatch: pytest.MonkeyPa
     )
     assert r.status_code == 200
     assert r.json()["status"] == "self_update_queued"
+    assert seen["expected_sha256"] == "0" * 64
 
 
 def test_rollback_happy(client: TestClient, monkeypatch: pytest.MonkeyPatch) -> None:
@@ -158,6 +167,47 @@ def test_update_without_sha256_is_rejected(client: TestClient) -> None:
     assert "sha256" in r.json()["detail"]
 
 
+def test_update_with_empty_sha256_is_rejected(client: TestClient) -> None:
+    # An explicit empty form value is treated the same as absent → 400.
+    r = client.post(
+        "/update",
+        files={"tarball": ("t.tgz", _tarball(), "application/gzip")},
+        data={"sha": "ABC", "sha256": ""},
+    )
+    assert r.status_code == 400
+    assert "sha256" in r.json()["detail"]
+
+
+def test_update_self_without_sha256_is_rejected(client: TestClient) -> None:
+    r = client.post(
+        "/update-self",
+        files={"tarball": ("t.tgz", _tarball(), "application/gzip")},
+        data={"confirm_self": "true"},
+    )
+    assert r.status_code == 400
+    assert "sha256" in r.json()["detail"]
+
+
+def test_update_mismatched_sha256_is_rejected_before_apply(
+    client: TestClient, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """End-to-end through the REAL executor verify: a non-matching digest is a
+    500 UpdateError and no extraction/pip happens (extract/_run_pip would be
+    reached only AFTER the digest check, so we assert they are never called)."""
+    called: list[str] = []
+    monkeypatch.setattr(ex, "extract_tarball", lambda *a, **k: called.append("extract"))
+    monkeypatch.setattr(ex, "_run_pip", lambda *a, **k: called.append("pip"))
+
+    r = client.post(
+        "/update",
+        files={"tarball": ("t.tgz", _tarball(), "application/gzip")},
+        data={"sha": "ABC", "sha256": "0" * 64},  # wrong digest for this tarball
+    )
+    assert r.status_code == 500, r.text
+    assert "mismatch" in r.json()["detail"]["error"]
+    assert called == []  # rejected before any extract/install
+
+
 # ------------------------- master-cert gate ---------------------------------
 
 
diff --git a/tests/updater/test_updater_executor.py b/tests/updater/test_updater_executor.py
index 3c081322..20f57b6b 100644
--- a/tests/updater/test_updater_executor.py
+++ b/tests/updater/test_updater_executor.py
@@ -8,6 +8,7 @@ against a ``tmp_path`` install dir.
 """
 from __future__ import annotations
 
+import hashlib
 import io
 import pathlib
 import subprocess
@@ -32,6 +33,11 @@ def _make_tarball(files: dict[str, str]) -> bytes:
     return buf.getvalue()
 
 
+def _digest(tarball: bytes) -> str:
+    """SHA-256 hex of the tarball — now mandatory on run_update/run_update_self."""
+    return hashlib.sha256(tarball).hexdigest()
+
+
 class _PipOK:
     returncode = 0
     stdout = ""
@@ -207,6 +213,40 @@ def test_run_update_rejects_malformed_sha256(
         )
 
 
+@pytest.mark.parametrize("missing", ["", "   ", None])
+def test_run_update_rejects_missing_sha256_fail_closed(
+    install_dir: pathlib.Path, agent_dir: pathlib.Path, missing: Any,
+) -> None:
+    """V12.1.2 fail-closed: an absent/empty digest is rejected BEFORE any
+    extraction or pip-install. No staging tree is produced."""
+    tb = _make_tarball({"x.txt": "y"})
+    with pytest.raises(ex.UpdateError, match="required but was missing or empty"):
+        ex.run_update(
+            tb, sha="S", expected_sha256=missing,  # type: ignore[arg-type]
+            install_dir=install_dir, agent_dir=agent_dir,
+        )
+    assert not (install_dir / "releases" / "active.new").exists()
+
+
+@pytest.mark.parametrize("missing", ["", "   ", None])
+def test_run_update_self_rejects_missing_sha256_fail_closed(
+    install_dir: pathlib.Path, missing: Any,
+) -> None:
+    active = install_dir / "releases" / "active"
+    active.mkdir()
+    (active / "marker").write_text("old-updater")
+    tb = _make_tarball({"marker": "new-updater"})
+    with pytest.raises(ex.UpdateError, match="required but was missing or empty"):
+        ex.run_update_self(
+            tb, sha="U", updater_install_dir=install_dir,
+            expected_sha256=missing,  # type: ignore[arg-type]
+            exec_cb=lambda a: None,
+        )
+    # Active untouched, nothing staged.
+    assert (install_dir / "releases" / "active" / "marker").read_text() == "old-updater"
+    assert not (install_dir / "releases" / "active.new").exists()
+
+
 def test_clean_stale_staging(install_dir: pathlib.Path) -> None:
     staging = install_dir / "releases" / "active.new"
     staging.mkdir()
@@ -229,7 +269,7 @@ def test_update_rotates_and_probes(
     monkeypatch.setattr(ex, "_probe_agent", lambda **_: (True, "ok"))
 
     tb = _make_tarball({"marker.txt": "new"})
-    result = ex.run_update(tb, sha="NEWSHA", install_dir=install_dir, agent_dir=agent_dir)
+    result = ex.run_update(tb, sha="NEWSHA", expected_sha256=_digest(tb), install_dir=install_dir, agent_dir=agent_dir)
 
     assert result["status"] == "updated"
     assert result["release"]["sha"] == "NEWSHA"
@@ -252,7 +292,7 @@ def test_update_first_install_without_previous(
     monkeypatch.setattr(ex, "_probe_agent", lambda **_: (True, "ok"))
 
     tb = _make_tarball({"marker.txt": "first"})
-    result = ex.run_update(tb, sha="S1", install_dir=install_dir, agent_dir=agent_dir)
+    result = ex.run_update(tb, sha="S1", expected_sha256=_digest(tb), install_dir=install_dir, agent_dir=agent_dir)
     assert result["status"] == "updated"
     assert not (install_dir / "releases" / "prev").exists()
 
@@ -273,7 +313,7 @@ def test_update_pip_failure_aborts_before_rotation(
 
     tb = _make_tarball({"marker.txt": "new"})
     with pytest.raises(ex.UpdateError, match="pip install failed") as ei:
-        ex.run_update(tb, sha="S", install_dir=install_dir, agent_dir=agent_dir)
+        ex.run_update(tb, sha="S", expected_sha256=_digest(tb), install_dir=install_dir, agent_dir=agent_dir)
     assert "resolver error" in ei.value.stderr
 
     # Nothing rotated — old active still live, no prev created.
@@ -309,7 +349,7 @@ def test_update_probe_failure_rolls_back(
 
     tb = _make_tarball({"marker.txt": "new"})
     with pytest.raises(ex.UpdateError, match="health probe") as ei:
-        ex.run_update(tb, sha="NEWSHA", install_dir=install_dir, agent_dir=agent_dir)
+        ex.run_update(tb, sha="NEWSHA", expected_sha256=_digest(tb), install_dir=install_dir, agent_dir=agent_dir)
     assert ei.value.rolled_back is True
     assert "connection refused" in ei.value.stderr
 
@@ -381,6 +421,7 @@ def test_update_self_rotates_and_calls_exec_cb(
     tb = _make_tarball({"marker": "new-updater"})
     result = ex.run_update_self(
         tb, sha="USHA", updater_install_dir=install_dir,
+        expected_sha256=_digest(tb),
         exec_cb=lambda argv: seen_argv.append(argv),
     )
     assert result["status"] == "self_update_queued"
@@ -412,7 +453,7 @@ def test_update_self_under_systemd_defers_to_systemctl(
     monkeypatch.setattr(ex.os, "execv", lambda *a, **k: pytest.fail("execv taken under systemd"))
 
     tb = _make_tarball({"marker": "new-updater"})
-    result = ex.run_update_self(tb, sha="USHA", updater_install_dir=install_dir)
+    result = ex.run_update_self(tb, sha="USHA", updater_install_dir=install_dir, expected_sha256=_digest(tb))
     assert result == {"status": "self_update_queued", "via": "systemd"}
     assert len(popen_calls) == 1
     sh_cmd = popen_calls[0]
@@ -431,7 +472,7 @@ def test_update_self_pip_failure_leaves_active_intact(
 
     tb = _make_tarball({"marker": "new-updater"})
     with pytest.raises(ex.UpdateError, match="pip install failed"):
-        ex.run_update_self(tb, sha="U", updater_install_dir=install_dir, exec_cb=lambda a: None)
+        ex.run_update_self(tb, sha="U", updater_install_dir=install_dir, expected_sha256=_digest(tb), exec_cb=lambda a: None)
     assert (install_dir / "releases" / "active" / "marker").read_text() == "old-updater"
     assert not (install_dir / "releases" / "active.new").exists()
 
diff --git a/tests/web/test_api_startup_guards.py b/tests/web/test_api_startup_guards.py
index fb6ba9b4..061d1b05 100644
--- a/tests/web/test_api_startup_guards.py
+++ b/tests/web/test_api_startup_guards.py
@@ -23,13 +23,6 @@ def _reload_api(monkeypatch: pytest.MonkeyPatch):
     return importlib.import_module("decnet.web.api")
 
 
-def _strip_pytest_vars(monkeypatch: pytest.MonkeyPatch) -> None:
-    import os
-    for k in list(os.environ):
-        if k.startswith("PYTEST"):
-            monkeypatch.delenv(k, raising=False)
-
-
 async def _run_lifespan_startup(api_mod) -> None:
     """Run the lifespan up to (but not past) yield, then unwind cleanly.
 
@@ -59,6 +52,7 @@ def test_master_api_refuses_to_start_in_agent_mode(
     monkeypatch.setenv("DECNET_MODE", "agent")
     monkeypatch.setenv("DECNET_DISALLOW_MASTER", "true")
     monkeypatch.setenv("DECNET_JWT_SECRET", "x" * 32)
+    monkeypatch.setenv("DECNET_CORS_ORIGINS", "http://localhost:8080")
     api = _reload_api(monkeypatch)
     with pytest.raises(RuntimeError, match="master-only"):
         asyncio.get_event_loop_policy().new_event_loop().run_until_complete(
@@ -74,6 +68,7 @@ def test_master_api_starts_when_dual_role_enabled(
     monkeypatch.setenv("DECNET_MODE", "agent")
     monkeypatch.setenv("DECNET_DISALLOW_MASTER", "false")
     monkeypatch.setenv("DECNET_JWT_SECRET", "x" * 32)
+    monkeypatch.setenv("DECNET_CORS_ORIGINS", "http://localhost:8080")
     api = _reload_api(monkeypatch)
     # Reaching the DB init phase means the gate passed; we don't need to
     # actually finish startup. Cancel via a synthetic exception that the
@@ -107,7 +102,7 @@ def test_master_api_eager_loads_jwt_secret_at_startup(
     monkeypatch.setenv("DECNET_MODE", "master")
     monkeypatch.setenv("DECNET_JWT_SECRET", "y" * 32)
     monkeypatch.setenv("DECNET_API_HOST", "127.0.0.1")
-    monkeypatch.delenv("DECNET_CORS_ORIGINS", raising=False)
+    monkeypatch.setenv("DECNET_CORS_ORIGINS", "http://localhost:8080")
     api = _reload_api(monkeypatch)
     import decnet.env as env_mod
 
@@ -130,3 +125,45 @@ def test_master_api_eager_loads_jwt_secret_at_startup(
     assert "DECNET_JWT_SECRET" in seen, (
         "lifespan must access env.DECNET_JWT_SECRET at startup"
     )
+
+
+# ---------------------------------------------------------------------------
+# V13.1.4 — CORS wildcard guard
+# ---------------------------------------------------------------------------
+
+def test_cors_wildcard_guard_function_raises() -> None:
+    """_check_cors_origins raises ValueError when '*' is in the list."""
+    from decnet.web.api import _check_cors_origins
+    with pytest.raises(ValueError, match="wildcard"):
+        _check_cors_origins(["*"])
+
+
+def test_cors_wildcard_among_explicit_origins_raises() -> None:
+    """Wildcard in a mixed list is still rejected."""
+    from decnet.web.api import _check_cors_origins
+    with pytest.raises(ValueError, match="wildcard"):
+        _check_cors_origins(["https://example.com", "*"])
+
+
+def test_cors_explicit_origins_pass() -> None:
+    """Explicit origin URLs pass the guard without raising."""
+    from decnet.web.api import _check_cors_origins
+    _check_cors_origins(["https://example.com", "https://app.internal"])
+
+
+def test_cors_wildcard_raises_in_lifespan(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Lifespan raises ValueError when DECNET_CORS_ORIGINS contains '*'.
+
+    Uses _reload_api to pick up the patched env; tests the full guard
+    path including the lifespan call to _check_cors_origins.
+    """
+    monkeypatch.setenv("DECNET_MODE", "master")
+    monkeypatch.setenv("DECNET_JWT_SECRET", "z" * 32)
+    monkeypatch.setenv("DECNET_CORS_ORIGINS", "*")
+    api = _reload_api(monkeypatch)
+    with pytest.raises(ValueError, match="wildcard"):
+        asyncio.get_event_loop_policy().new_event_loop().run_until_complete(
+            _run_lifespan_startup(api)
+        )
diff --git a/tests/web/test_validate_public_binding.py b/tests/web/test_validate_public_binding.py
index 880b167f..4649d2b7 100644
--- a/tests/web/test_validate_public_binding.py
+++ b/tests/web/test_validate_public_binding.py
@@ -1,9 +1,9 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 """validate_public_binding refuses footgun configs at master startup.
 
-The validator no-ops under pytest by design (so unit tests in unrelated
-modules don't have to set five env vars per fixture); these tests strip
-the PYTEST_* vars before calling it so the real code path runs.
+The validator no-ops under the test harness (DECNET_TESTING=1) by design (so
+unit tests in unrelated modules don't have to set five env vars per fixture);
+these tests clear that flag before calling it so the real code path runs.
 """
 from __future__ import annotations
 
@@ -20,18 +20,17 @@ def _reimport_env(monkeypatch: pytest.MonkeyPatch):
     return importlib.import_module("decnet.env")
 
 
-def _strip_pytest_vars(monkeypatch: pytest.MonkeyPatch) -> None:
-    import os
-    for k in list(os.environ):
-        if k.startswith("PYTEST"):
-            monkeypatch.delenv(k, raising=False)
+def _strip_test_flag(monkeypatch: pytest.MonkeyPatch) -> None:
+    # The validator short-circuits on DECNET_TESTING=1 (set globally by
+    # conftest). Clear it so the real production code path runs.
+    monkeypatch.delenv("DECNET_TESTING", raising=False)
 
 
 def test_validator_noop_on_loopback_binding(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setenv("DECNET_API_HOST", "127.0.0.1")
     monkeypatch.setenv("DECNET_CORS_ORIGINS", "http://localhost:8080")
     env = _reimport_env(monkeypatch)
-    _strip_pytest_vars(monkeypatch)
+    _strip_test_flag(monkeypatch)
     env.validate_public_binding()  # no raise
 
 
@@ -41,7 +40,7 @@ def test_validator_rejects_loopback_cors_on_public_bind(
     monkeypatch.setenv("DECNET_API_HOST", "0.0.0.0")
     monkeypatch.setenv("DECNET_CORS_ORIGINS", "http://localhost:8080")
     env = _reimport_env(monkeypatch)
-    _strip_pytest_vars(monkeypatch)
+    _strip_test_flag(monkeypatch)
     with pytest.raises(ValueError, match="loopback origin"):
         env.validate_public_binding()
 
@@ -52,7 +51,7 @@ def test_validator_accepts_public_cors_on_public_bind(
     monkeypatch.setenv("DECNET_API_HOST", "0.0.0.0")
     monkeypatch.setenv("DECNET_CORS_ORIGINS", "https://dashboard.example.com")
     env = _reimport_env(monkeypatch)
-    _strip_pytest_vars(monkeypatch)
+    _strip_test_flag(monkeypatch)
     env.validate_public_binding()  # no raise
 
 
@@ -63,7 +62,7 @@ def test_validator_rejects_plaintext_canary_on_public_bind(
     monkeypatch.setenv("DECNET_CORS_ORIGINS", "https://dashboard.example.com")
     monkeypatch.setenv("DECNET_CANARY_HTTP_BASE", "http://canary.example.com:8088")
     env = _reimport_env(monkeypatch)
-    _strip_pytest_vars(monkeypatch)
+    _strip_test_flag(monkeypatch)
     with pytest.raises(ValueError, match="plaintext HTTP"):
         env.validate_public_binding()
 
@@ -77,14 +76,28 @@ def test_validator_allows_loopback_canary_even_on_public_bind(
     monkeypatch.setenv("DECNET_CORS_ORIGINS", "https://dashboard.example.com")
     monkeypatch.setenv("DECNET_CANARY_HTTP_BASE", "http://localhost:8088")
     env = _reimport_env(monkeypatch)
-    _strip_pytest_vars(monkeypatch)
+    _strip_test_flag(monkeypatch)
     env.validate_public_binding()  # no raise
 
 
-def test_validator_skips_under_pytest(monkeypatch: pytest.MonkeyPatch) -> None:
-    # With PYTEST_* still in env (default), even a misconfigured env passes —
-    # this is the deliberate bypass so unrelated tests don't trip on it.
+def test_validator_skips_under_test_harness(monkeypatch: pytest.MonkeyPatch) -> None:
+    # With DECNET_TESTING=1 still in env (set by conftest), even a misconfigured
+    # env passes — this is the deliberate bypass so unrelated tests don't trip.
+    monkeypatch.setenv("DECNET_TESTING", "1")
     monkeypatch.setenv("DECNET_API_HOST", "0.0.0.0")
     monkeypatch.setenv("DECNET_CORS_ORIGINS", "http://localhost:8080")
     env = _reimport_env(monkeypatch)
     env.validate_public_binding()  # no raise — guard short-circuits
+
+
+def test_validator_pytest_var_leak_does_not_bypass(monkeypatch: pytest.MonkeyPatch) -> None:
+    # V2.1.7 regression: a leaked PYTEST_* env var must NOT disable the guard.
+    # With DECNET_TESTING cleared, a misconfigured public binding still raises
+    # even though a PYTEST_* var is present.
+    monkeypatch.delenv("DECNET_TESTING", raising=False)
+    monkeypatch.setenv("PYTEST_CURRENT_TEST", "x")
+    monkeypatch.setenv("DECNET_API_HOST", "0.0.0.0")
+    monkeypatch.setenv("DECNET_CORS_ORIGINS", "http://localhost:8080")
+    env = _reimport_env(monkeypatch)
+    with pytest.raises(ValueError, match="loopback origin"):
+        env.validate_public_binding()