{"id":"UBUNTU-CVE-2026-42011","details":"A flaw was found in gnutls. This vulnerability occurs because permitted name constraints were incorrectly ignored when previous Certificate Authorities (CAs) only had excluded name constraints. A remote attacker could exploit this to bypass critical name constraint checks during certificate validation. This bypass could lead to the acceptance of invalid certificates, potentially enabling spoofing or man-in-the-middle attacks against affected systems.","modified":"2026-07-14T23:44:42.820272846Z","published":"2026-05-07T15:16:00Z","related":["USN-8284-1","USN-8539-1"],"upstream":["CVE-2026-42011"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-42011"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-42011"},{"type":"REPORT","url":"https://www.gnutls.org/security-new.html#GNUTLS-SA-2026-04-29-6"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8284-1"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8539-1"}],"affected":[{"package":{"name":"gnutls28","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/gnutls28?arch=source&distro=esm-infra%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.5.18-1ubuntu1.6+esm4"}]}],"versions":["3.5.8-6ubuntu3","3.5.17-1ubuntu1","3.5.17-1ubuntu3","3.5.18-1ubuntu1","3.5.18-1ubuntu1.1","3.5.18-1ubuntu1.2","3.5.18-1ubuntu1.3","3.5.18-1ubuntu1.4","3.5.18-1ubuntu1.5","3.5.18-1ubuntu1.6","3.5.18-1ubuntu1.6+esm1","3.5.18-1ubuntu1.6+esm2","3.5.18-1ubuntu1.6+esm3"],"ecosystem_specific":{"binaries":[{"binary_version":"3.5.18-1ubuntu1.6+esm4","binary_name":"gnutls-bin"},{"binary_name":"libgnutls-dane0","binary_version":"3.5.18-1ubuntu1.6+esm4"},{"binary_name":"libgnutls-openssl27","binary_version":"3.5.18-1ubuntu1.6+esm4"},{"binary_name":"libgnutls30","binary_version":"3.5.18-1ubuntu1.6+esm4"},{"binary_version":"3.5.18-1ubuntu1.6+esm4","binary_name":"libgnutlsxx28"}],"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42011.json"}},{"package":{"name":"gnutls28","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/gnutls28?arch=source&distro=esm-infra%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.6.13-2ubuntu1.12+esm3"}]}],"versions":["3.6.9-5ubuntu1","3.6.9-5ubuntu2","3.6.10-5","3.6.11.1-2","3.6.11.1-2ubuntu2","3.6.13-2ubuntu1","3.6.13-2ubuntu1.1","3.6.13-2ubuntu1.2","3.6.13-2ubuntu1.3","3.6.13-2ubuntu1.6","3.6.13-2ubuntu1.7","3.6.13-2ubuntu1.8","3.6.13-2ubuntu1.9","3.6.13-2ubuntu1.10","3.6.13-2ubuntu1.11","3.6.13-2ubuntu1.12","3.6.13-2ubuntu1.12+esm1","3.6.13-2ubuntu1.12+esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"gnutls-bin","binary_version":"3.6.13-2ubuntu1.12+esm3"},{"binary_version":"3.6.13-2ubuntu1.12+esm3","binary_name":"guile-gnutls"},{"binary_name":"libgnutls-dane0","binary_version":"3.6.13-2ubuntu1.12+esm3"},{"binary_version":"3.6.13-2ubuntu1.12+esm3","binary_name":"libgnutls-openssl27"},{"binary_name":"libgnutls30","binary_version":"3.6.13-2ubuntu1.12+esm3"},{"binary_name":"libgnutlsxx28","binary_version":"3.6.13-2ubuntu1.12+esm3"}],"availability":"Available with Ubuntu Pro (Infra-only): 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subscription 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with Ubuntu Pro: 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subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42011.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"},{"type":"Ubuntu","score":"medium"}]}