OAuthLib: Token grants can use attacker-supplied client_id for authorization after authenticating a different client

Date Oct 30, 2026
Type Vendor advisory
Signal High-risk advisory
Vendor / Product PyPI ยท oauthlib
CVE CVE-2026-118669
High-risk advisory CVE-2026-118669

Summary

OAuthLib: Token grants can use attacker-supplied client_id for authorization after authenticating a different client

Why it matters

GitHub has published a reviewed security advisory for oauthlib. Prioritize it with other application dependency updates, especially because EPSS places it in the 24% percentile.

Operator check

Check whether oauthlib is present in application dependency manifests, lockfiles, or build images. Review the GitHub advisory and upgrade to a patched version where available. CVSS score: 8.4. EPSS probability: 0.3%; percentile: 24%.

Sources

PatchBrief uses public sources. It does not scan environments, verify exposure, or replace vendor guidance.