Medium severity · published Sep 3, 2021
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…
6.1
CVSS
1.7%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)1.7% · higher than 78% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DL
Debian Linux · Debian
10.0 · source: NVD
FE
Fedora · Fedoraproject
35; 36 · source: NVD
MA
Mod Auth Openidc · Openidc
before 2.4.9.4 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-39191
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-39191
Patch
https://github.com/zmartzone/mod_auth_openidc/commit/03e6bfb446f4e3f27c003d30d6a433e5dd8e2b3d
Exploit
https://github.com/zmartzone/mod_auth_openidc/issues/672
Release Notes
https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9.4
Vendor Advisory
https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-2pgf-8h6h-gqg2
Mailing List
https://lists.debian.org/debian-lts-announce/2023/07/msg00020.html
lists.fedoraproject.org
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/32RGPW5LZDLDTB7MKZIGAHPSLFOUNWR5/
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