Authlib up to 1.6.9/1.7.0 OAuth 2.0 Authorization Endpoint redirect

Summaryinfo

A vulnerability identified as problematic has been detected in Authlib up to 1.6.9/1.7.0. Affected by this vulnerability is an unknown functionality of the component OAuth 2.0 Authorization Endpoint. Performing a manipulation results in redirect. This vulnerability is identified as CVE-2026-41479. The attack can be initiated remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Authlib up to 1.6.9/1.7.0. This affects some unknown functionality of the component OAuth 2.0 Authorization Endpoint. The manipulation with an unknown input leads to a redirect vulnerability. CWE is classifying the issue as CWE-601. A web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a Redirect. This simplifies phishing attacks. This is going to have an impact on integrity. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-41479 since 04/20/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1204.001 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 322299 (Linux Distros Unpatched Vulnerability : CVE-2026-41479), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.6.10 eliminates this vulnerability. Applying the patch 3be08468201a7766a93012ce149ea12822cab096 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (322299). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

• Authlib

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.6.0
• 1.6.1
• 1.6.2
• 1.6.3
• 1.6.4
• 1.6.5
• 1.6.6
• 1.6.7
• 1.6.8
• 1.6.9
• 1.7.0

License

• open-source

Website

• Product: https://github.com/authlib/authlib/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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