Vulnerability Description
OAuthLib is an implementation of the OAuth request-signing logic for Python 3.6+. Prior to 4.0.0, the client_credentials and Resource Owner Password Credentials token grant handlers can authenticate request.client as one confidential client while retaining an attacker-supplied request.client_id for validate_grant_type and validate_scopes. A lower-privilege authenticated client can therefore cause grant and scope authorization to use another client's identity when an application validator relies on the documented client_id argument, potentially issuing tokens with unauthorized grants or scopes. Validators that authorize exclusively from request.client may not be affected. This issue is fixed in version 4.0.0.
Related Weaknesses (CWE)
References
- https://github.com/oauthlib/oauthlib/commit/c951a1d09f99f14e3240973fa83c4f4287d4
- https://github.com/oauthlib/oauthlib/pull/920
- https://github.com/oauthlib/oauthlib/releases/tag/v4.0.0
- https://github.com/oauthlib/oauthlib/security/advisories/GHSA-7984-qgvg-3j9c
FAQ
What is CVE-2026-118669?
CVE-2026-118669 is a documented vulnerability. OAuthLib is an implementation of the OAuth request-signing logic for Python 3.6+. Prior to 4.0.0, the client_credentials and Resource Owner Password Credentials token grant handlers can authenticate r...
How severe is CVE-2026-118669?
CVSS scoring is not yet available for CVE-2026-118669. Check NVD for updates.
Is there a patch for CVE-2026-118669?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.