Improper Input Validation Affecting python-authlib package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applicationsSnyk Learn
Learn about Improper Input Validation vulnerabilities in an interactive lesson.
Start learning- Snyk IDSNYK-DEBIAN12-PYTHONAUTHLIB-13534781
- published12 Oct 2025
- disclosed10 Oct 2025
Introduced: 10 Oct 2025
NewCVE-2025-61920 (opens in a new tab)How to fix?
There is no fixed version for Debian:12 python-authlib.
NVD Description
Note: Versions mentioned in the description apply only to the upstream python-authlib package and not the python-authlib package as distributed by Debian.
See How to fix? for Debian:12 relevant fixed versions and status.
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.