Metrics
Affected Vendors & Products
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-r9gp-7f88-9r54 | Lemur: JWT verifier honors attacker-supplied alg, enabling ATO |
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Tue, 18 Aug 2026 20:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Netflix
Netflix lemur |
|
| Vendors & Products |
Netflix
Netflix lemur |
Tue, 18 Aug 2026 20:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Tue, 18 Aug 2026 19:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Lemur manages TLS certificate creation. Prior to 1.9.2, the JWT verifier in lemur/auth/service.py:130-137 used fetch_token_header to read header_data["alg"] from an unverified token and passed that attacker-controlled value to decode_with_multiple_secrets. PyJWT 2.x rejects alg=none with the configured key, so the flaw is a defense-in-depth gap rather than a direct authentication bypass in the shipped configuration. The unpinned algorithm can become exploitable after an asymmetric-signing migration through algorithm confusion, and it weakens algorithm-based anomaly detection because the token chooses the recorded value. A separate disclosure of LEMUR_TOKEN_SECRET would also permit forged HS256 tokens, although that disclosure is an independent prerequisite. The fix introduces the server-controlled LEMUR_TOKEN_ALGORITHMS allowlist and defaults it to HS256. This issue is fixed in version 1.9.2. | |
| Title | Lemur : JWT verifier trusts attacker-supplied alg from token header — defense-in-depth gap; chain-dependent ATO with secret disclosure | |
| Weaknesses | CWE-347 | |
| References |
| |
| Metrics |
cvssV3_1
|
Projects
Sign in to view the affected projects.
Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-08-18T19:35:55.129Z
Reserved: 2026-06-16T15:13:28.165Z
Link: CVE-2026-55165
Updated: 2026-08-18T19:35:50.379Z
Status : Received
Published: 2026-08-18T19:16:58.647
Modified: 2026-08-18T20:17:18.960
Link: CVE-2026-55165
No data.
OpenCVE Enrichment
Updated: 2026-08-18T20:30:17Z
Github GHSA