Resource Exhaustion Affecting python-authlib package, versions <0.15.5-1ubuntu0.1~esm1


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.43% (36th percentile)

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  • Snyk IDSNYK-UBUNTU2204-PYTHONAUTHLIB-13712416
  • published27 Feb 2026
  • disclosed22 Oct 2025

Introduced: 22 Oct 2025

CVE-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 Ubuntu:22.04 python-authlib to version 0.15.5-1ubuntu0.1~esm1 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 Ubuntu. See How to fix? for Ubuntu:22.04 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