CVE-2026-33308
Mod_gnutls is a TLS module for Apache HTTPD based on GnuTLS.
Published Mar 24, 2026 · updated Jun 17, 2026 · mod gnutls project mod gnutls
Mod_gnutls is a TLS module for Apache HTTPD based on GnuTLS. Prior to version 0.13.0, code for client certificate verification did not check the key purpose as set in the Extended Key Usage extension. An attacker with access to the private key for a valid certificate issued by a CA trusted for TLS client authentication but designated for a different purpose could have used that certificate to improperly access resources requiring TLS client authentication. Server configurations that do not use client certificates ( , the default) are not affected. The problem has been fixed in version 0.13.0 by rewriting certificate verification to use , and requiring key purpose id-kp-clientAuth (also known as in GnuTLS) by default if the Extended Key Usage extension is present. The new option allows overriding the expected key purpose if needed (please see the manual for details). Behavior for certificates without an Extended Key Usage extension is unchanged. If dedicated (sub-)CAs are used for issuing TLS client certificates only (not for any other purposes) the issue has no practical impact.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Mar 24, 2026 · NIST NVD
Detected
Mod_gnutls is a TLS module for Apache HTTPD based on GnuTLS. Prior to version 0.13.0, code for client certificate verification did not check the key purpose as set in the Extended Key Usage extension. An attacker with access to the private key for a valid certificate issued by a CA trusted for TLS client authentication but designated for a different purpose could have used that certificate to impr
Jun 17, 2026 · NIST NVD
Updated
Mod_gnutls is a TLS module for Apache HTTPD based on GnuTLS. Prior to version 0.13.0, code for client certificate verification did not check the key purpose as set in the Extended Key Usage extension. An attacker with access to the private key for a valid certificate issued by a CA trusted for TLS client authentication but designated for a different purpose could have used that certificate to impr
Affected
- cpe mod gnutls project/mod gnutlsversion unspecified
Sources
- CVE.orgVulnerability recordCVE-2026-33308
Official CVE identifier
cve.org - NIST NVDVulnerability recordCVE-2026-33308
Mod_gnutls is a TLS module for Apache HTTPD based on GnuTLS. Prior to version 0.13.0, code for client certificate verification did not check the key purpose as set in the Extended Key Usage extension. An attacker with access to the private key for a valid certificate issued by a
nvd.nist.gov