VULNERABILITY INTELLIGENCE
CVE-2021-39191
CVSS score4.7 MEDIUM
EPSS probability1.74%
CISA KEVNot currently listed
Published2021-09-03
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
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.
Weakness classification
- security-advisories@github.com: CWE-601
- nvd@nist.gov: CWE-601
Primary references
- security-advisories@github.com — Patch, Third Party Advisory
- security-advisories@github.com — Exploit
- security-advisories@github.com — Release Notes
- security-advisories@github.com — Vendor Advisory
- security-advisories@github.com — Mailing List
- security-advisories@github.com
- security-advisories@github.com
- af854a3a-2127-422b-91ae-364da2661108 — Patch, Third Party Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Exploit
- af854a3a-2127-422b-91ae-364da2661108 — Release Notes
- af854a3a-2127-422b-91ae-364da2661108 — Vendor Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Mailing List