CVE-2025-31492

Description

mod_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.

How to fix CVE-2025-31492

To remediate CVE-2025-31492, upgrade the affected package to a fixed version below.

• —upgrade to 2.4.9.4-0+deb11u5 or later
• —upgrade to 2.4.9.4-0+deb11u5 or later
• —upgrade to 2.4.12.3-2+deb12u3 or later

Is CVE-2025-31492 being exploited?

Low — EPSS is 0.4%, meaning exploitation activity has not been observed at scale.

Affected packages (3)

• from 0, < 2.4.9.4-0+deb11u5
• from 0, < 2.4.9.4-0+deb11u5
• from 0, < 2.4.12.3-2+deb12u3

CVSS scores

References (1)

• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2025-31492