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Vulnerabilities

Vulnerability · CVE-2026-33308

Mod_gnutls is a TLS module for Apache HTTPD based on GnuTLS.

Published Mar 24, 2026 · catalog updated Jun 17, 2026 · mod gnutls project mod gnutls

Check if you run it

No confirmed exploitation is on record for CVE-2026-33308. EPSS is 0.24%. Act only if a listed version of mod gnutls project mod gnutls is installed.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.9
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.24%
Remediation
Advisory link
Affected products
cpe 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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe mod gnutls project/mod gnutlsversion unspecified

How to fix CVE-2026-33308

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-33308. EPSS is 0.24%. Act only if a listed version of mod gnutls project mod gnutls is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-295: Improper Certificate Validation. EPSS 0.24%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. 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

  2. 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

Sources

  • CVE.orgVulnerability recordCVE-2026-33308

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-33308

    30-day exploitation probability 0.2%

    first.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

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.