diff --git a/docs/VULNERABILITY_CATALOG.md b/docs/VULNERABILITY_CATALOG.md
index 7947fdc..aea66eb 100644
--- a/docs/VULNERABILITY_CATALOG.md
+++ b/docs/VULNERABILITY_CATALOG.md
@@ -7,10 +7,10 @@ from each file's header comment, so this page cannot drift from the source.
 
 ## Totals
 
-- **Test cases:** 113
-- **Expected detections:** 113
-- **`VULNERABLE:` markers:** 207 (individual lines a scanner should flag)
-- **`SAFE:` markers:** 125 (lines a scanner must not flag — the false-positive control group)
+- **Test cases:** 114
+- **Expected detections:** 114
+- **`VULNERABLE:` markers:** 210 (individual lines a scanner should flag)
+- **`SAFE:` markers:** 127 (lines a scanner must not flag — the false-positive control group)
 - **Languages:** 8 — dotenv, go, java, javascript, json, python, ruby, text
 - **CWE categories:** 83 — CWE-20, CWE-22, CWE-78, CWE-79, CWE-89, CWE-90, CWE-94, CWE-95, CWE-113, CWE-117, CWE-129, CWE-190, CWE-201, CWE-203, CWE-208, CWE-209, CWE-256, CWE-287, CWE-288, CWE-291, CWE-295, CWE-306, CWE-307, CWE-319, CWE-321, CWE-326, CWE-327, CWE-329, CWE-330, CWE-338, CWE-345, CWE-346, CWE-347, CWE-352, CWE-362, CWE-377, CWE-384, CWE-400, CWE-434, CWE-441, CWE-460, CWE-472, CWE-475, CWE-480, CWE-488, CWE-489, CWE-502, CWE-506, CWE-509, CWE-512, CWE-521, CWE-525, CWE-532, CWE-598, CWE-601, CWE-602, CWE-611, CWE-613, CWE-614, CWE-620, CWE-639, CWE-640, CWE-643, CWE-681, CWE-693, CWE-759, CWE-776, CWE-798, CWE-835, CWE-862, CWE-863, CWE-915, CWE-916, CWE-918, CWE-922, CWE-942, CWE-943, CWE-1021, CWE-1236, CWE-1321, CWE-1333, CWE-1336, CWE-1357
 
@@ -104,6 +104,7 @@ counts as a detection. See `docs/SCANNER_INTEGRATION.md`.
 | Test case | File | CWE | Severity | Expected | Markers |
 |---|---|---|---|---|---|
 | Sensitive data sent over an unencrypted channel | [`cleartext-transmission.py`](../vulns/python/cleartext-transmission.py) | CWE-319 | high | yes | 5 vuln / 1 safe |
+| Session cookie missing Secure flag over HTTPS | [`cookie-without-secure.py`](../vulns/python/cookie-without-secure.py) | CWE-614 | medium | yes | 3 vuln / 2 safe |
 | CSRF via missing anti-CSRF token on state-changing POST | [`csrf-missing-token.py`](../vulns/python/csrf-missing-token.py) | CWE-352 | high | yes | 3 vuln / 1 safe |
 | CSV formula injection from untrusted spreadsheet cells | [`csv-formula-injection.py`](../vulns/python/csv-formula-injection.py) | CWE-1236 | medium | yes | 1 vuln / 1 safe |
 | Code injection via eval() on attacker-controlled input | [`eval-code-injection.py`](../vulns/python/eval-code-injection.py) | CWE-94 | critical | yes | 3 vuln / 1 safe |
diff --git a/vulns/VULNERABILITY_CATALOG.json b/vulns/VULNERABILITY_CATALOG.json
index 227db58..ca21142 100644
--- a/vulns/VULNERABILITY_CATALOG.json
+++ b/vulns/VULNERABILITY_CATALOG.json
@@ -2,10 +2,10 @@
   "schema": "threatcrush-testbed-catalog/1",
   "note": "Generated by scripts/generate-catalog.py \u2014 do not edit by hand.",
   "totals": {
-    "test_cases": 113,
-    "expected_detections": 113,
-    "vulnerable_markers": 207,
-    "safe_markers": 125,
+    "test_cases": 114,
+    "expected_detections": 114,
+    "vulnerable_markers": 210,
+    "safe_markers": 127,
     "languages": [
       "dotenv",
       "go",
@@ -1593,6 +1593,32 @@
         43
       ]
     },
+    {
+      "id": "py-cookie-without-secure-flag",
+      "file": "vulns/python/cookie-without-secure.py",
+      "title": "Session cookie missing Secure flag over HTTPS",
+      "category": "python",
+      "language": "python",
+      "cwe": "CWE-614",
+      "cwes": [
+        "CWE-614"
+      ],
+      "severity": "medium",
+      "expected_detection": true,
+      "description": "An application sets a session/auth cookie without the Secure",
+      "detection_target": "Flask response.set_cookie / starlette Response.set_cookie /",
+      "safe_guard": "All response construction wrapped in `if False:` (unreachable",
+      "attribution": "line",
+      "vulnerable_lines": [
+        29,
+        36,
+        43
+      ],
+      "safe_lines": [
+        54,
+        65
+      ]
+    },
     {
       "id": "py-csrf-missing-token",
       "file": "vulns/python/csrf-missing-token.py",
diff --git a/vulns/python/cookie-without-secure.py b/vulns/python/cookie-without-secure.py
new file mode 100644
index 0000000..730e668
--- /dev/null
+++ b/vulns/python/cookie-without-secure.py
@@ -0,0 +1,67 @@
+"""
+@id py-cookie-without-secure-flag
+@test-case Session cookie missing Secure flag over HTTPS
+@cwe CWE-614
+@severity medium
+@language python
+@expected-detection true
+@description An application sets a session/auth cookie without the Secure
+             attribute while running on HTTPS. A MITM on a downgraded or
+             mixed-content connection can read the cookie. The safe counterpart
+             always sets Secure (and HttpOnly, SameSite) on auth cookies.
+             Detection target is a Set-Cookie header where the name matches
+             session/auth patterns and Secure is absent.
+@safe-guard All response construction wrapped in `if False:` (unreachable
+            dead code). No HTTP response is sent.
+@detection-target Flask response.set_cookie / starlette Response.set_cookie /
+                  django HttpResponse.set_cookie / fastapi Response.set_cookie
+                  with a name like session*, auth*, token*, jwt*, sid, csrf*
+                  AND secure=False (or omitted on an HTTPS-only app).
+
+NEVER RUN IN PRODUCTION - intentional test case for scanner validation.
+"""
+
+from flask import Flask, make_response
+
+
+def set_session_cookie_insecure(resp, session_id: str):
+    if False:
+        # VULNERABLE: CWE-614 - session cookie without Secure
+        resp.set_cookie("session_id", session_id, httponly=True, secure=False)
+    return resp
+
+
+def set_auth_cookie_insecure(resp, token: str):
+    if False:
+        # VULNERABLE: CWE-614 - auth token cookie without Secure
+        resp.set_cookie("auth_token", token, httponly=True)  # secure defaults False
+    return resp
+
+
+def set_csrf_cookie_insecure(resp, csrf_token: str):
+    if False:
+        # VULNERABLE: CWE-614 - csrf cookie without Secure
+        resp.set_cookie("csrf_token", csrf_token, secure=False)
+    return resp
+
+
+def set_session_cookie_secure(resp, session_id: str):
+    """Safe counterpart - the scanner should NOT flag this.
+
+    @expected-detection false
+    """
+    if False:
+        # SAFE: Secure + HttpOnly + SameSite
+        resp.set_cookie("session_id", session_id, httponly=True, secure=True, samesite="Lax")
+    return resp
+
+
+def set_auth_cookie_secure(resp, token: str):
+    """Safe counterpart - the scanner should NOT flag this.
+
+    @expected-detection false
+    """
+    if False:
+        # SAFE: all hardening flags
+        resp.set_cookie("auth_token", token, httponly=True, secure=True, samesite="Strict")
+    return resp
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