CVSS 3.1
6.1 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:NCVE-2021-39191
Medium (6.1). EPSS 1.7% chance of exploitation in the next 30 days.
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.
Severity
- EPSS
- 1.7% chance of exploitation in the next 30 days; higher than 77% of CVEs (scores of 2026-10-31)
- CWE
- CWE-601
- Published
- Modified
- Record from
- the NVD, synced
Affected
- debian:debian_linux
- fedoraproject:fedora
- openidc:mod_auth_openidc
References
- https://github.com/zmartzone/mod_auth_openidc/commit/03e6bfb446f4e3f27c003d30d6a433e5dd8e2b3d
- https://github.com/zmartzone/mod_auth_openidc/issues/672
- https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9.4
- https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-2pgf-8h6h-gqg2
- https://lists.debian.org/debian-lts-announce/2023/07/msg00020.html