CVE-2026-41479
Authlib OAuth 2.0 authorization endpoint open redirects to attacker-controlled redirect_uri on unsupported response_type
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to 1.6.10 and 1.7.1, Authlib's OAuth 2.0 authorization endpoint can be turned into an unauthenticated open redirect when a request uses an unsupported response_type and supplies an attacker-controlled redirect_uri. The vulnerable behavior happens before client lookup and before any redirect URI validation. As a result, an attacker does not need a valid client registration, an authenticated user, or any prior state. A single request to the authorization endpoint is enough to obtain a 302 Location response to an arbitrary attacker-controlled URL. This vulnerability is fixed in 1.6.10 and 1.7.1.
- Affected
- authlib
- CVSS v3.1 GITHUB
- 5.4 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N - EPSS
- 0.26% chance of exploitation in the next 30 days, 16th percentile
- Published
- 2026-06-22
- Updated
- 2026-06-23
Proof-of-concept exploits (1)
Security advisories
- authlib/authlib/security/advisories/GHSA-w8p2-r796-3vmq
- authlib/authlib/commit/3be08468201a7766a93012ce149ea12822cab096