Resource Exhaustion Affecting python-authlib package, versions <1.6.5-1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.04% (14th percentile)

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 applications

Snyk Learn

Learn about Resource Exhaustion vulnerabilities in an interactive lesson.

Start learning
  • Snyk IDSNYK-DEBIANUNSTABLE-PYTHONAUTHLIB-13704154
  • published24 Oct 2025
  • disclosed22 Oct 2025

Introduced: 22 Oct 2025

NewCVE-2025-62706  (opens in a new tab)
CWE-400  (opens in a new tab)
CWE-770  (opens in a new tab)

How to fix?

Upgrade Debian:unstable python-authlib to version 1.6.5-1 or higher.

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:unstable 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 JWE zip=DEF path performs unbounded DEFLATE decompression. A very small ciphertext can expand into tens or hundreds of megabytes on decrypt, allowing an attacker who can supply decryptable tokens to exhaust memory and CPU and cause denial of service. This issue has been patched in version 1.6.5. Workarounds for this issue involve rejecting or stripping zip=DEF for inbound JWEs at the application boundary, forking and add a bounded decompression guard via decompressobj().decompress(data, MAX_SIZE)) and returning an error when output exceeds a safe limit, or enforcing strict maximum token sizes and fail fast on oversized inputs; combine with rate limiting.

CVSS Base Scores

version 3.1