CVE-2026-54072
Received Received - Intake

Open Redirect in Authorizer Authentication Server

Publication date: 2026-09-11

Last updated on: 2026-09-11

Assigner: GitHub, Inc.

Description
Authorizer is an open-source, self-hostable authentication and authorization server. Prior to version 2.2.1, the `/authorize` endpoint accepts any `redirect_uri` without validating it against `AllowedOrigins`. When `response_type=token` or `response_type=id_token`, the server appends `access_token`, `id_token`, and `refresh_token` as query parameters and issues a 302 redirect to the attacker-supplied URL. An unauthenticated attacker can obtain the required `client_id` from the public `/graphql?query={meta{client_id}}` endpoint. A partial fix was applied in v2.0.1 to other handlers (`oauth_login`, `verify_email`, `magic_link_login`, `forgot_password`, `invite_members`, `oauth_callback`) but `/authorize` was not included. Version 2.2.1 contains a more complete fix.

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Meta Information

Published
2026-09-11
Last Modified
2026-09-11
Generated
2026-09-12
AI Q&A
2026-09-11
EPSS Evaluated
N/A
NVD
CVE-2026-54072
EUVD
EUVD-2026-76187

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
authorizer authorizer to 2.2.1 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-601 The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.

Attack-Flow Graph

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Executive Summary

This vulnerability affects the Authorizer OAuth2 server versions prior to 2.2.1. The `/authorize` endpoint does not validate the `redirect_uri` parameter against allowed origins. Attackers can exploit this to craft malicious URLs that leak OAuth2 tokens (access_token, id_token, refresh_token) via a 302 redirect to an attacker-controlled domain. The attack requires no authentication since the client_id can be obtained from a public GraphQL query.

Detection Guidance

Check if your Authorizer server version is below 2.2.1 by running: curl -s http://<your-server>/graphql?query={meta{version}}. If the version is less than 2.2.1, the system is vulnerable. Also inspect network logs for unexpected 302 redirects to unknown domains during OAuth flows.

Impact Analysis

An unauthenticated attacker can obtain your OAuth2 tokens by tricking you into clicking a malicious link. These tokens can then be used to impersonate you, gaining unauthorized access to your accounts and sensitive data. The impact includes potential data breaches, account takeover, and loss of confidentiality and integrity.

Compliance Impact

This vulnerability can lead to unauthorized access to personal data, violating GDPR's data protection principles and HIPAA's security requirements. It may result in data breaches, non-compliance with privacy regulations, and potential legal penalties due to compromised confidentiality and integrity of sensitive information.

Mitigation Strategies

Upgrade Authorizer to version 2.2.1 or later immediately. If upgrading is not possible, restrict access to the `/authorize` endpoint temporarily until the update is applied. Monitor for suspicious OAuth token leaks in logs.

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