VDB
DEBIAN-CVE-2025-59420
DEBIAN-CVE-2025-59420
PUBLISHED
CVSS 7.5 HIGH
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.4, Authlib’s JWS verification accepts tokens that declare unknown critical header parameters (crit), violating RFC 7515 “must‑understand” semantics. An attacker can craft a signed token with a critical header (for example, bork or cnf) that strict verifiers reject but Authlib accepts. In mixed‑language fleets, this enables split‑brain verification and can lead to policy bypass, replay, or privilege escalation. This issue has been patched in version 1.6.4.
Risk Scores
CVSS v3.1
7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Debian:11 | python-authlib | 0.15.4-1, 0, 0.15.4-1 |
| Debian:12 | python-authlib | 1.6.1-1, 1.6.7-1, 1.6.8-1 |
| Debian:13 | python-authlib | 0, 1.6.0-1, 1.6.0-1+deb13u1 |
| Debian:14 | python-authlib | 1.6.1-1, 1.6.3-1, 0 |
Timeline
- Sep 22, 2025 CVE Published
- May 16, 2026 CVE Updated