# CVE-2026-44681: Authlib open redirect in OIDC Implicit and Hybrid grants

Source: https://junglewise.ai/threats/cve-2026-44681-authlib-open-redirect-in-oidc-implicit-and-hybrid-grants  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-27. Updated: 2026-06-09  
License: CC BY 4.0 with a link back

CVE-2026-44681 · Severity: medium · CVSS 6.1 · Published 2026-05-27

Authlib, a library used to implement login and authorization services, contains a flaw that allows attackers to redirect users to malicious websites. By sending a specially crafted login request that omits a required security setting, an attacker can trick the server into sending a user to a phishing page. This can be used to steal user credentials by making the malicious site appear as if it is part of a trusted login process.

Technologies: [authlib (PyPI)](https://junglewise.ai/threats/technologies/authlib). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-44681 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-44681 being exploited in the wild.

**How severe is CVE-2026-44681?** Medium severity, with a CVSS score of 6.1, published 27 May 2026.

**Which products and versions are affected?** authlib (PyPI) ECOSYSTEM:introduced=0,fixed=1.6.12, ECOSYSTEM:introduced=1.7.0,fixed=1.7.1.

**Is there a fix for CVE-2026-44681?** Yes. authlib (PyPI): upgrade to 1.6.12, 1.7.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-44681 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-44681?** Check whether you run authlib (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- authlib (PyPI): upgrade to 1.6.12, 1.7.1 or later

  ```sh
  pip install "authlib>=1.7.1"
  ```


## Technical details

An open redirect exists in Authlib's `OpenIDImplicitGrant` and `OpenIDHybridGrant` implementations. The vulnerability occurs because the `validate_authorization_request` method checks for the presence of the 'openid' scope before validating the `redirect_uri` against the registered client configuration. If the scope is missing, the library raises an `InvalidScopeError` that includes the unvalidated `redirect_uri` from the request payload. When this error is processed, the server issues an HTTP 302 redirect to the attacker-supplied URL. This bypasses standard OAuth 2.0 security requirements that mandate URI validation before redirection. The issue is fixed in versions 1.6.12 and 1.7.1.

## Affected products

- Authlib Authlib <= 1.6.11, 1.7.0

## Identifiers

- CVE-2026-44681
- GHSA-r95x-qfjj-fjj2
- PYSEC-2026-188

## Timeline

- 2026-05-07: advisory: GitHub Advisory published
- 2026-05-13: disclosed

## References

- [https://api.github.com/users/y011d4](https://api.github.com/users/y011d4)
- [https://github.com/y011d4](https://github.com/y011d4)
- [https://api.github.com/users/y011d4/gists%7B/gist_id%7D](https://api.github.com/users/y011d4/gists%7B/gist_id%7D)
- [https://api.github.com/users/y011d4/repos](https://api.github.com/users/y011d4/repos)
- [https://avatars.githubusercontent.com/u/27393930?v=4](https://avatars.githubusercontent.com/u/27393930?v=4)
- [https://api.github.com/users/y011d4/events%7B/privacy%7D](https://api.github.com/users/y011d4/events%7B/privacy%7D)

## Related threats

- [Authlib client configuration endpoint authorization bypass](https://junglewise.ai/threats/cve-2026-116672-authlib-is-a-python-library-which-builds-oauth-and-openid)
- [Authlib RFC 9101 server-side request forgery in request_uri parameter](https://junglewise.ai/threats/cve-2026-114620-authlib-is-a-python-library-which-builds-oauth-and-openid)
- [Authlib OpenID Connect scope validation bypass](https://junglewise.ai/threats/cve-2026-114619-authlib-is-a-python-library-which-builds-oauth-and-openid)
- [Authlib JWT Bearer Grant audience validation bypass](https://junglewise.ai/threats/cve-2026-114618-authlib-is-a-python-library-which-builds-oauth-and-openid)
- [Authlib nonce validation bypass in OpenID token parsing](https://junglewise.ai/threats/cve-2026-114617-authlib-is-a-python-library-which-builds-oauth-and-openid)