UBUNTU-CVE-2026-33308

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Source
https://ubuntu.com/security/CVE-2026-33308
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33308.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-33308
Upstream
Published
2026-03-24T03:16:00Z
Modified
2026-04-02T17:31:26Z
Severity
  • 6.8 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N CVSS Calculator
  • 5.9 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

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 (GnuTLSClientVerify ignore, the default) are not affected. The problem has been fixed in version 0.13.0 by rewriting certificate verification to use gnutls_certificate_verify_peers(), and requiring key purpose id-kp-clientAuth (also known as tls_www_client in GnuTLS) by default if the Extended Key Usage extension is present. The new GnuTLSClientKeyPurpose 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.

References

Affected packages

Ubuntu:16.04:LTS / mod-gnutls

Package

Name
mod-gnutls
Purl
pkg:deb/ubuntu/mod-gnutls@0.7.3-0ubuntu1?arch=source&distro=xenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.6-1.1
0.7.3-0ubuntu1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "0.7.3-0ubuntu1",
            "binary_name": "libapache2-mod-gnutls"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33308.json"

Ubuntu:18.04:LTS / mod-gnutls

Package

Name
mod-gnutls
Purl
pkg:deb/ubuntu/mod-gnutls@0.8.2-3ubuntu1?arch=source&distro=bionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.8.2-3ubuntu1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "0.8.2-3ubuntu1",
            "binary_name": "libapache2-mod-gnutls"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33308.json"

Ubuntu:20.04:LTS / mod-gnutls

Package

Name
mod-gnutls
Purl
pkg:deb/ubuntu/mod-gnutls@0.9.0-1.1ubuntu1?arch=source&distro=focal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.8.2-3ubuntu1
0.9.0-1.1ubuntu1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "0.9.0-1.1ubuntu1",
            "binary_name": "libapache2-mod-gnutls"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33308.json"

Ubuntu:22.04:LTS / mod-gnutls

Package

Name
mod-gnutls
Purl
pkg:deb/ubuntu/mod-gnutls@0.9.0-1.1ubuntu1?arch=source&distro=jammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.9.0-1.1ubuntu1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "0.9.0-1.1ubuntu1",
            "binary_name": "libapache2-mod-gnutls"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33308.json"