CVE-2026-33307
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. In versions prior to 0.12.3 and 0.13.0, code for client certificate verification imported the certificate chain sent by the client into a fixed size array without checking the number of certificates is less than or equal to the array size. is a for a pointer to an opaque GnuTLS structure created using with before importing certificate data into it, so no attacker-controlled data was written into the stack buffer, but writing a pointer after the last array element generally triggered a segfault, and could theoretically cause stack corruption otherwise (not observed in practice). Server configurations that do not use client certificates ( , the default) are not affected. The problem has been fixed in version 0.12.3 by checking the length of the provided certificate chain and rejecting it if it exceeds the buffer length, and in version 0.13.0 by rewriting certificate verification to use , removing the need for the buffer entirely. There is no workaround. Version 0.12.3 provides the minimal fix for users of 0.12.x who do not wish to upgrade to 0.13.0 yet.
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. In versions prior to 0.12.3 and 0.13.0, code for client certificate verification imported the certificate chain sent by the client into a fixed size array without checking the number of certificates is less than or equal to the array size. is a for a pointer to an opaque GnuTLS structure created using with before importing certificate da
Jun 17, 2026 · NIST NVD
Updated
Mod_gnutls is a TLS module for Apache HTTPD based on GnuTLS. In versions prior to 0.12.3 and 0.13.0, code for client certificate verification imported the certificate chain sent by the client into a fixed size array without checking the number of certificates is less than or equal to the array size. is a for a pointer to an opaque GnuTLS structure created using with before importing certificate da
Affected
- cpe mod gnutls project/mod gnutlsversion unspecified
Sources
- CVE.orgVulnerability recordCVE-2026-33307
Official CVE identifier
cve.org - NIST NVDVulnerability recordCVE-2026-33307
Mod_gnutls is a TLS module for Apache HTTPD based on GnuTLS. In versions prior to 0.12.3 and 0.13.0, code for client certificate verification imported the certificate chain sent by the client into a fixed size array without checking the number of certif
nvd.nist.gov