Vulnerability 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, `oidc_validate_redirect_url()` does not parse URLs the same way as most browsers do. As a result, this function can be bypassed and leads to an Open Redirect vulnerability in the logout functionality. This bug has been fixed in version 2.4.9 by replacing any backslash of the URL to redirect with slashes to address a particular breaking change between the different specifications (RFC2396 / RFC3986 and WHATWG). As a workaround, this vulnerability can be mitigated by configuring `mod_auth_openidc` to only allow redirection whose destination matches a given regular expression.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Openidc | Mod Auth Openidc | < 2.4.9 |
| Apache | Http Server | >= 2.0.0, <= 2.4.48 |
| Fedoraproject | Fedora | 33 |
Related Weaknesses (CWE)
References
- https://daniel.haxx.se/blog/2017/01/30/one-url-standard-please/ExploitThird Party Advisory
- https://github.com/zmartzone/mod_auth_openidc/commit/3a115484eb927bc6daa5737dd84PatchThird Party Advisory
- https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9Release NotesThird Party Advisory
- https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-xm4c-5wm5Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/04/msg00034.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://security.netapp.com/advisory/ntap-20210902-0001/Third Party Advisory
- https://www.oracle.com/security-alerts/cpuapr2022.htmlPatchThird Party Advisory
- https://daniel.haxx.se/blog/2017/01/30/one-url-standard-please/ExploitThird Party Advisory
- https://github.com/zmartzone/mod_auth_openidc/commit/3a115484eb927bc6daa5737dd84PatchThird Party Advisory
- https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9Release NotesThird Party Advisory
- https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-xm4c-5wm5Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/04/msg00034.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
FAQ
What is CVE-2021-32786?
CVE-2021-32786 is a vulnerability with a CVSS score of 4.7 (MEDIUM). 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...
How severe is CVE-2021-32786?
CVE-2021-32786 has been rated MEDIUM with a CVSS base score of 4.7/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-32786?
Check the references section above for vendor advisories and patch information. Affected products include: Openidc Mod Auth Openidc, Apache Http Server, Fedoraproject Fedora.