Package vulnerability, severity high

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

Published October 30, 2026, updated October 31, 2026

OAuthLib: Token grants can use attacker-supplied client_id for authorization after authenticating a different client. Source: GHSA-7984-qgvg-3j9c (CVE-2026-118669).

What's affected

• oauthlib (pypi)<4.0.0

What to do

1. Upgrade oauthlib to 4.0.0 or later.

Check whether you were affected

Pharon tells teams automatically when this affects something they run. To check a machine, run this in Claude Code with the Pharon plugin, in the repository that uses it:

/pharon:check-incident ghsa-7984-qgvg-3j9c

References

• https://osv.dev/vulnerability/GHSA-7984-qgvg-3j9c
• https://github.com/oauthlib/oauthlib/security/advisories/GHSA-7984-qgvg-3j9c
• https://nvd.nist.gov/vuln/detail/CVE-2026-118669
• https://github.com/oauthlib/oauthlib/pull/920
• https://github.com/oauthlib/oauthlib/commit/c951a1d09f99f14e3240973fa83c4f4287d4753d
• https://github.com/oauthlib/oauthlib
• https://github.com/oauthlib/oauthlib/releases/tag/v4.0.0

Notice ghsa-7984-qgvg-3j9c, signed with key feed-prod-2026-10 (Ed25519). The Pharon CLI verifies the signature before using a notice.