Vulnerability Description
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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Openidc | Mod Auth Openidc | < 2.4.9.4 |
| Fedoraproject | Fedora | 35 |
| Debian | Debian Linux | 10.0 |
Related Weaknesses (CWE)
References
- https://github.com/zmartzone/mod_auth_openidc/commit/03e6bfb446f4e3f27c003d30d6aPatchThird 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-8h6hVendor Advisory
- https://lists.debian.org/debian-lts-announce/2023/07/msg00020.htmlMailing List
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://github.com/zmartzone/mod_auth_openidc/commit/03e6bfb446f4e3f27c003d30d6aPatchThird 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-8h6hVendor Advisory
- https://lists.debian.org/debian-lts-announce/2023/07/msg00020.htmlMailing List
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
FAQ
What is CVE-2021-39191?
CVE-2021-39191 is a vulnerability with a CVSS score of 4.7 (MEDIUM). 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...
How severe is CVE-2021-39191?
CVE-2021-39191 has been rated MEDIUM with a CVSS base score of 4.7/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-39191?
Check the references section above for vendor advisories and patch information. Affected products include: Openidc Mod Auth Openidc, Fedoraproject Fedora, Debian Debian Linux.