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. In affected versions missing input validation on mod_auth_openidc_session_chunks cookie value makes the server vulnerable to a denial of service (DoS) attack. An internal security audit has been conducted and the reviewers found that if they manipulated the value of the mod_auth_openidc_session_chunks cookie to a very large integer, like 99999999, the server struggles with the request for a long time and finally gets back with a 500 error. Making a few requests of this kind caused our server to become unresponsive. Attackers can craft requests that would make the server work very hard (and possibly become unresponsive) and/or crash with minimal effort. This issue has been addressed in version Users are advised to upgrade. There are no known workarounds for this vulnerability.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1064183

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
libapache2-mod-auth-openidc (PTS)buster2.3.10.2-1+deb10u1vulnerable
buster (security)
bullseye (security), bullseye2.4.9.4-0+deb11u3vulnerable

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs


[bookworm] - libapache2-mod-auth-openidc <no-dsa> (Minor issue)
[bullseye] - libapache2-mod-auth-openidc <no-dsa> (Minor issue) (v2.4.15.2)

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