CVE catalog
CVE-2025-59420
Authlib vulnerabilities
- Severity
- High · CVSS 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.26% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | python-authlib | sid | 1.7.2-2 | fixed |
| Debian | python-authlib | forky | 1.7.2-2 | fixed |
| Debian | python-authlib | trixie | 1.6.0-1+deb13u1 | fixed |
| Debian | python-authlib | bookworm | 1.2.0-1+deb12u1 | fixed |
| Debian | python-authlib | bookworm-security | 1.2.0-1+deb12u2 | fixed |
| Ubuntu | python-authlib | noble | Not reported | vulnerable |
| Ubuntu | python-authlib | noble | 1.3.0-1ubuntu0.1~esm1 | fixed |
| Ubuntu | python-authlib-doc | noble | 1.3.0-1ubuntu0.1~esm1 | fixed |
| Ubuntu | python3-authlib | noble | 1.3.0-1ubuntu0.1~esm1 | fixed |
| Cpe | authlib | Not reported | 1.6.4 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | python-authlib | source | sid | 1.6.4-1 | not yet assigned | Not reported | Not reported |
| Debian | python-authlib | source | forky | 1.6.4-1 | not yet assigned | Not reported | Not reported |
| Debian | python-authlib | source | trixie | 1.6.0-1+deb13u1 | not yet assigned | Not reported | Not reported |
| Debian | python-authlib | source | bookworm | 1.2.0-1+deb12u1 | not yet assigned | Not reported | Not reported |
| Ubuntu | python-authlib | deb | noble | 1.3.0-1ubuntu0.1~esm1 | Not reported | Not reported | Not reported |
| Ubuntu | python-authlib-doc | deb | noble | 1.3.0-1ubuntu0.1~esm1 | Not reported | Not reported | Not reported |
| Ubuntu | python3-authlib | deb | noble | 1.3.0-1ubuntu0.1~esm1 | Not reported | Not reported | Not reported |
| Cpe | authlib | cpe | Not reported | 1.6.4 | Not reported | NVD-CVE-2025-59420 | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [python3-authlib]Fixed
Source package: [python-authlib]
Details (4)
1.2.0-1+deb12u1· all · bookwormFixed · Fixed:
1.2.0-1+deb12u1usn · python-authlib · debian · bookworm; usn · python-authlib · debian · 12
1.2.0-1+deb12u1· all · bookwormFixed · Fixed:
1.2.0-1+deb12u1usn · python-authlib · debian · bookworm; usn · python-authlib · debian · 12
1.2.0-1+deb12u2· all · bookworm-securityFixed · Fixed:
1.2.0-1+deb12u1usn · python-authlib · debian · bookworm; usn · python-authlib · debian · 12
1.2.0-1+deb12u2· all · bookworm-securityFixed · Fixed:
1.2.0-1+deb12u1usn · python-authlib · debian · bookworm; usn · python-authlib · debian · 12
- [python-authlib-doc]Fixed
Source package: [python-authlib]
Details (4)
1.2.0-1+deb12u1· all · bookwormFixed · Fixed:
1.2.0-1+deb12u1usn · python-authlib · debian · bookworm; usn · python-authlib · debian · 12
1.2.0-1+deb12u1· all · bookwormFixed · Fixed:
1.2.0-1+deb12u1usn · python-authlib · debian · bookworm; usn · python-authlib · debian · 12
1.2.0-1+deb12u2· all · bookworm-securityFixed · Fixed:
1.2.0-1+deb12u1usn · python-authlib · debian · bookworm; usn · python-authlib · debian · 12
1.2.0-1+deb12u2· all · bookworm-securityFixed · Fixed:
1.2.0-1+deb12u1usn · python-authlib · debian · bookworm; usn · python-authlib · debian · 12
[Debian 13 (Trixie)]
- [python3-authlib]Fixed
Source package: [python-authlib]
Details (2)
1.6.0-1+deb13u1· all · trixieFixed · Fixed:
1.6.0-1+deb13u1usn · python-authlib · debian · 13
1.6.0-1+deb13u1· all · trixieFixed · Fixed:
1.6.0-1+deb13u1usn · python-authlib · debian · 13
- [python-authlib-doc]Fixed
Source package: [python-authlib]
Details (2)
1.6.0-1+deb13u1· all · trixieFixed · Fixed:
1.6.0-1+deb13u1usn · python-authlib · debian · 13
1.6.0-1+deb13u1· all · trixieFixed · Fixed:
1.6.0-1+deb13u1usn · python-authlib · debian · 13
Observed:
References
- [https://nvd.nist.gov/vuln/detail/CVE-2025-59420]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2025-59420]
- [https://security-tracker.debian.org/tracker/CVE-2025-59420]
- [https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-59420.json]
- [https://ubuntu.com/security/notices/USN-8065-1]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [Ubuntu Security Notices (USN)]