CVE-2021-39191

mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In versions prior to 2.4.9.4, the 3rd-party init SSO functionality of mod_auth_openidc was reported to be vulnerable to an open redirect attack by supplying a crafted URL in the `target_link_uri` parameter. A patch in version 2.4.9.4 made it so that the `OIDCRedirectURLsAllowed` setting must be applied to the `target_link_uri` parameter. There are no known workarounds aside from upgrading to a patched version.

• CWE-601
• CWE-601

• https://github.com/zmartzone/mod_auth_openidc/commit/03e6bfb446f4e3f27c003d30d6a433e5dd8e2b3dPatch, Third Party Advisory
• https://github.com/zmartzone/mod_auth_openidc/issues/672Exploit
• https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9.4Release Notes
• https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-2pgf-8h6h-gqg2Vendor Advisory
• https://lists.debian.org/debian-lts-announce/2023/07/msg00020.htmlMailing List
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/32RGPW5LZDLDTB7MKZIGAHPSLFOUNWR5/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RHXO4O4G2UQS7X6OQJCVZKHZAQ7SAIFB/
• https://github.com/zmartzone/mod_auth_openidc/commit/03e6bfb446f4e3f27c003d30d6a433e5dd8e2b3dPatch, Third Party Advisory
• https://github.com/zmartzone/mod_auth_openidc/issues/672Exploit
• https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9.4Release Notes
• https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-2pgf-8h6h-gqg2Vendor Advisory
• https://lists.debian.org/debian-lts-announce/2023/07/msg00020.htmlMailing List
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/32RGPW5LZDLDTB7MKZIGAHPSLFOUNWR5/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RHXO4O4G2UQS7X6OQJCVZKHZAQ7SAIFB/

Published

Sep 3, 2021

Last Modified

Jun 17, 2026

Status

Modified

• One Click Account Takeover in GranolaHow a notification link broke out of Electron and led to a one-click account takeover.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2021-39185Http4s is a minimal, idiomatic Scala interface for HTTP serv…9.1
• CVE-2021-39186GlobalNewFiles is a MediaWiki extension maintained by Mirahe…6.1
• CVE-2021-39187Parse Server is an open source backend that can be deployed …7.5
• CVE-2021-39189Pimcore is an open source data & experience management platf…5.3
• CVE-2021-3919A potential security vulnerability has been identified in OM…9.8
• CVE-2021-39190The SCCM plugin for GLPI is a plugin to synchronize computer…5.3
• CVE-2021-39192Ghost is a Node.js content management system. An error in th…7.2
• CVE-2021-39193Frontier is Substrate's Ethereum compatibility layer. Prior …5.3
• CVE-2021-39194kaml is an open source implementation of the YAML format wit…6.5
• CVE-2021-39195Misskey is an open source, decentralized microblogging platf…6.5
• CVE-2021-39196pcapture is an open source dumpcap web service interface . I…6.5
• CVE-2021-39197better_errors is an open source replacement for the standard…8.8