SB2026051194 - Open redirect in authlib

Description

This security bulletin contains information about 1 vulnerability.

1) Open redirect (CVE-ID: CVE-2026-44681)

The vulnerability allows a remote attacker to redirect users to an attacker-controlled URL.

The vulnerability exists due to url redirection to an untrusted site in OpenIDImplicitGrant and OpenIDHybridGrant authorization request validation when processing authorization requests that omit the openid scope. A remote attacker can send a specially crafted authorization request with an attacker-controlled redirect_uri to redirect users to an attacker-controlled URL.

Exploitation requires an authorization server deployment that registers the OIDC Implicit or Hybrid grant types, and user interaction is required.

Remediation

Install update from vendor's website.

References

• https://github.com/authlib/authlib/security/advisories/GHSA-r95x-qfjj-fjj2
• https://github.com/authlib/authlib/commit/3be08468