CVE-2025-31492

NameCVE-2025-31492
Descriptionmod_auth_openidc is an OpenID Certified authentication and authorization module for the Apache 2.x HTTP server that implements the OpenID Connect Relying Party functionality. Prior to 2.4.16.11, a bug in a mod_auth_openidc results in disclosure of protected content to unauthenticated users. The conditions for disclosure are an OIDCProviderAuthRequestMethod POST, a valid account, and there mustn't be any application-level gateway (or load balancer etc) protecting the server. When you request a protected resource, the response includes the HTTP status, the HTTP headers, the intended response (the self-submitting form), and the protected resource (with no headers). This is an example of a request for a protected resource, including all the data returned. In the case where mod_auth_openidc returns a form, it has to return OK from check_userid so as not to go down the error path in httpd. This means httpd will try to issue the protected resource. oidc_content_handler is called early, which has the opportunity to prevent the normal output being issued by httpd. oidc_content_handler has a number of checks for when it intervenes, but it doesn't check for this case, so the handler returns DECLINED. Consequently, httpd appends the protected content to the response. The issue has been patched in mod_auth_openidc versions >= 2.4.16.11.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-4129-1, DSA-5904-1
Debian Bugs1102413

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
libapache2-mod-auth-openidc (PTS)bullseye2.4.9.4-0+deb11u4vulnerable
bullseye (security)2.4.9.4-0+deb11u5fixed
bookworm2.4.12.3-2+deb12u2vulnerable
bookworm (security)2.4.12.3-2+deb12u3fixed
trixie, sid2.4.16.11-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
libapache2-mod-auth-openidcsourcebullseye2.4.9.4-0+deb11u5DLA-4129-1
libapache2-mod-auth-openidcsourcebookworm2.4.12.3-2+deb12u3DSA-5904-1
libapache2-mod-auth-openidcsource(unstable)2.4.16.11-11102413

Notes

https://github.com/OpenIDC/mod_auth_openidc/security/advisories/GHSA-59jp-rwph-878r
Fixed by: https://github.com/OpenIDC/mod_auth_openidc/commit/b59b8ad63411857090ba1088e23fe414c690c127 (v2.4.16.11)

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