CVE catalog

CVE-2021-39191

libapache2-mod-auth-openidc: CVE-2021-39191

[CVE catalog]

Severity
Medium · CVSS 6.1CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Published
Source
[NVD] · [CVE record]
EPSS
1.74% · Oct 25, 2026

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.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

DistributionPackageReleaseVersionStatus
Debianlibapache2-mod-auth-openidcsid2.4.20.3-1fixed
Debianlibapache2-mod-auth-openidcforky2.4.20.3-1fixed
Debianlibapache2-mod-auth-openidctrixie2.4.17-1fixed
Debianlibapache2-mod-auth-openidctrixie-security2.4.17-1+deb13u1fixed
Debianlibapache2-mod-auth-openidcbookworm2.4.12.3-2+deb12u4fixed
Debianlibapache2-mod-auth-openidcbookworm-security2.4.12.3-2+deb12u5fixed
Suseapache2-mod_auth_openidclinux enterprise module for server applications 15 sp42.3.8-150100.3.22.1fixed
Suseapache2-mod_auth_openidclinux enterprise real time 15 sp32.3.8-150100.3.22.1fixed
Opensuseapache2-mod_auth_openidcleap 15.42.3.8-150100.3.22.1fixed
Ubuntulibapache2-mod-auth-openidc18.042.1.6-1vulnerable
Ubuntulibapache2-mod-auth-openidc18.042.3.1-2vulnerable
Ubuntulibapache2-mod-auth-openidc18.042.3.2-1vulnerable
Ubuntulibapache2-mod-auth-openidc18.042.3.2-1build1vulnerable
Ubuntulibapache2-mod-auth-openidc18.042.3.3-1build1vulnerable
Ubuntulibapache2-mod-auth-openidc20.042.3.10.2-1vulnerable
Ubuntulibapache2-mod-auth-openidc20.042.4.0.4-1vulnerable
Ubuntulibapache2-mod-auth-openidc20.042.4.1-1vulnerable

Fixed-version evidence

DistributionPackageTypeReleaseFixed versionUrgencyOriginBugs
Debianlibapache2-mod-auth-openidcsourcesid2.4.9.4-1not yet assignedNot reported[993648]
Debianlibapache2-mod-auth-openidcsourceforky2.4.9.4-1not yet assignedNot reported[993648]
Debianlibapache2-mod-auth-openidcsourcetrixie2.4.9.4-1not yet assignedNot reported[993648]
Debianlibapache2-mod-auth-openidcsourcebookworm2.4.9.4-1not yet assignedNot reported[993648]
Suseapache2-mod_auth_openidcrpmlinux enterprise module for server applications 15 sp42.3.8-150100.3.22.1Not reportedSUSE-SU-2023:0215-1Not reported
Suseapache2-mod_auth_openidcrpmlinux enterprise real time 15 sp32.3.8-150100.3.22.1Not reportedSUSE-SU-2023:0215-1Not reported
Opensuseapache2-mod_auth_openidcrpmleap 15.42.3.8-150100.3.22.1Not reportedSUSE-SU-2023:0215-1Not reported

[Debian bug #993648]

OpenFactory catalog packages

Matching against OpenFactory catalog package versions is in progress.

[Debian 12 (Bookworm)]

  • [libapache2-mod-auth-openidc]Unknown
    Details (4)

    • 2.4.12.3-2+deb12u4 · amd64 · bookworm

      Fixed · Fixed: 2.4.9.4-1

      dsa · libapache2-mod-auth-openidc · debian · bookworm; dsa · libapache2-mod-auth-openidc · debian · 12

    • 2.4.12.3-2+deb12u4 · arm64 · bookworm

      Fixed · Fixed: 2.4.9.4-1

      dsa · libapache2-mod-auth-openidc · debian · bookworm; dsa · libapache2-mod-auth-openidc · debian · 12

    • 2.4.12.3-2+deb12u4 · amd64 · bookworm-security

      Fixed · Fixed: 2.4.9.4-1

      dsa · libapache2-mod-auth-openidc · debian · bookworm; dsa · libapache2-mod-auth-openidc · debian · 12

    • 2.4.12.3-2+deb12u4 · arm64 · bookworm-security

      Fixed · Fixed: 2.4.9.4-1

      dsa · libapache2-mod-auth-openidc · debian · bookworm; dsa · libapache2-mod-auth-openidc · debian · 12

[Debian 13 (Trixie)]

  • [libapache2-mod-auth-openidc]Unknown
    Details (3)

    • 2.4.17-1 · amd64 · trixie

      Fixed · Fixed: 2.4.9.4-1

      dsa · libapache2-mod-auth-openidc · debian · 13

    • 2.4.17-1 · arm64 · trixie

      Fixed · Fixed: 2.4.9.4-1

      dsa · libapache2-mod-auth-openidc · debian · 13

    • 2.4.17-1+deb13u1 · amd64 · trixie-security

      Fixed · Fixed: 2.4.9.4-1

      dsa · libapache2-mod-auth-openidc · debian · 13

Observed:

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]