CVE-2025-61920: PYSEC-2026-1203 - Authlib is vulnerable to Denial of Service via Oversized JOSE Segments

CVE-2025-61920 · Severity: low · CVSS 3.1 · Published 2026-07-07

Authlib is vulnerable to Denial of Service via Oversized JOSE Segments

Technologies: authlib (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2025-61920 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2025-61920 being exploited in the wild.
How severe is CVE-2025-61920?
Low severity, with a CVSS score of 3.1, published 7 July 2026.
Which products and versions are affected?
authlib (PyPI) ECOSYSTEM:introduced=0,fixed=1.6.5.
Is there a fix for CVE-2025-61920?
Yes. authlib (PyPI): upgrade to 1.6.5 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2025-61920?
Check whether you run authlib (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • authlib (PyPI): upgrade to 1.6.5 or later
    pip install "authlib>=1.6.5"

Affected products

  • authlib (PyPI) ECOSYSTEM:introduced=0,fixed=1.6.5

Identifiers

  • CVE-2025-61920
  • GHSA-pq5p-34cr-23v9
  • PYSEC-2026-1203

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