Home/CVE/mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Co
CVE

CVE-2021-39191

mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Co

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.

MEDIUM · CVSS 4.7 EPSS 0.00306
Schedule remediation
  • Public exploit or PoC is available
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-601URL Redirection to Untrusted Site ('Open Redirect')
CWE-601URL Redirection to Untrusted Site ('Open Redirect')
▤

Affected Products & Versions

3
openidc mod auth openidc< 2.4.9.4
fedoraproject fedoraall versions
debian linuxall versions
⚠

Public Exploits & PoCs

1
pocgithub.com · issues/672github.com
▣

Scoring & Timeline

4.7
MEDIUM · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD03 Sep 2021 · 02:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
⚑

Vendor Advisories

5
suse-csafSUSE-SU-2025:4532-1
suse-csafSUSE-SU-2023:0215-1
msrcCVE-2021-39191
suse-csafSUSE-SU-2021:3352-1
rhsaRHSA-2022:1823Moderate
🔗

References & Sources

6
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/zmartzone/mod_auth_openidc/commit/03e6bfb446f4e3f27c003d30d6a433e5dd8e2b3dPatchThird Party Advisory
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/
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