CVE catalog
CVE-2025-61920
Authlib vulnerabilities
- Severity
- High · CVSS 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.64% · Oct 25, 2026
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.5, Authlib’s JOSE implementation accepts unbounded JWS/JWT header and signature segments. A remote attacker can craft a token whose base64url‑encoded header or signature spans hundreds of megabytes. During verification, Authlib decodes and parses the full input before it is rejected, driving CPU and memory consumption to hostile levels and enabling denial of service. Version 1.6.5 patches the issue. Some temporary workarounds are available. Enforce input size limits before handing tokens to Authlib and/or use application-level throttling to reduce amplification risk.
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 | 1.6.5 | fixed |
| Ubuntu | python-authlib | pro | 1.6.0-1 | vulnerable |
| Ubuntu | python-authlib | pro | 1.6.5-1 | vulnerable |
| Ubuntu | python-authlib | pro | 1.6.6-1 | vulnerable |
| Ubuntu | python-authlib | pro | 1.6.7-1 | vulnerable |
| Ubuntu | python-authlib | pro | 1.6.7-1ubuntu0.1~esm1 | vulnerable |
| Ubuntu | python-authlib | 25.10 | 1.5.1-1 | vulnerable |
| Ubuntu | python-authlib | 25.10 | 1.5.2-1 | vulnerable |
| Ubuntu | python-authlib | 25.10 | 1.6.0-1 | vulnerable |
| Opensuse | python-Authlib | tumbleweed | 1.6.5-1.1 | fixed |
| Suse | python-Authlib | linux enterprise module for python 3 15 sp6 | 1.3.1-150600.3.6.1 | fixed |
| Suse | python-Authlib | linux enterprise module for python 3 15 sp7 | 1.3.1-150600.3.6.1 | fixed |
| Opensuse | python-Authlib | leap 15.6 | 1.3.1-150600.3.6.1 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | python-authlib | source | sid | 1.6.5-1 | not yet assigned | Not reported | Not reported |
| Debian | python-authlib | source | forky | 1.6.5-1 | 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 | 1.6.5 | Not reported | NVD-CVE-2025-61920 | Not reported |
| Opensuse | python-Authlib | rpm | tumbleweed | 1.6.5-1.1 | Not reported | OPENSUSE-SU-2025:15629-1 | Not reported |
| Suse | python-Authlib | rpm | linux enterprise module for python 3 15 sp6 | 1.3.1-150600.3.6.1 | Not reported | SUSE-SU-2025:3754-1 | Not reported |
| Suse | python-Authlib | rpm | linux enterprise module for python 3 15 sp7 | 1.3.1-150600.3.6.1 | Not reported | SUSE-SU-2025:3754-1 | Not reported |
| Opensuse | python-Authlib | rpm | leap 15.6 | 1.3.1-150600.3.6.1 | Not reported | SUSE-SU-2025:3754-1 | Not reported |
OpenFactory catalog packages
[openSUSE Tumbleweed]
- [python313-Authlib]Unknown
Source package: [python-Authlib]
Details (1)
1.7.2-3.1· noarch · tumbleweedUnknown · Fixed:
1.6.5-1.1Version impact unknown
usn · python-Authlib · opensuse · tumbleweed
- [python314-Authlib]Unknown
Source package: [python-Authlib]
Details (1)
1.7.2-3.1· noarch · tumbleweedUnknown · Fixed:
1.6.5-1.1Version impact unknown
usn · python-Authlib · opensuse · tumbleweed
[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://ftp.suse.com/pub/projects/security/csaf/suse-su-2025_3754-1.json]
- [https://nvd.nist.gov/vuln/detail/CVE-2025-61920]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2025-61920]
- [https://osv.dev/vulnerability/SUSE-SU-2025:3754-1]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2025-61920]
- [https://osv.dev/vulnerability/openSUSE-SU-2025:15629-1]
- [https://security-tracker.debian.org/tracker/CVE-2025-61920]
- [https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-61920.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] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]