ubuntu-cve-2026-42011
Vulnerability from osv_ubuntu
Published
2026-05-07 15:16
Modified
2026-07-06 14:11
Summary
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.


{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "gnutls-bin",
            "binary_version": "3.5.18-1ubuntu1.6+esm3"
          },
          {
            "binary_name": "libgnutls-dane0",
            "binary_version": "3.5.18-1ubuntu1.6+esm3"
          },
          {
            "binary_name": "libgnutls-openssl27",
            "binary_version": "3.5.18-1ubuntu1.6+esm3"
          },
          {
            "binary_name": "libgnutls30",
            "binary_version": "3.5.18-1ubuntu1.6+esm3"
          },
          {
            "binary_name": "libgnutlsxx28",
            "binary_version": "3.5.18-1ubuntu1.6+esm3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "gnutls28",
        "purl": "pkg:deb/ubuntu/gnutls28@3.5.18-1ubuntu1.6+esm3?arch=source\u0026distro=esm-infra/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "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_name": "gnutls-bin",
            "binary_version": "3.6.13-2ubuntu1.12+esm2"
          },
          {
            "binary_name": "guile-gnutls",
            "binary_version": "3.6.13-2ubuntu1.12+esm2"
          },
          {
            "binary_name": "libgnutls-dane0",
            "binary_version": "3.6.13-2ubuntu1.12+esm2"
          },
          {
            "binary_name": "libgnutls-openssl27",
            "binary_version": "3.6.13-2ubuntu1.12+esm2"
          },
          {
            "binary_name": "libgnutls30",
            "binary_version": "3.6.13-2ubuntu1.12+esm2"
          },
          {
            "binary_name": "libgnutlsxx28",
            "binary_version": "3.6.13-2ubuntu1.12+esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "gnutls28",
        "purl": "pkg:deb/ubuntu/gnutls28@3.6.13-2ubuntu1.12+esm2?arch=source\u0026distro=esm-infra/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "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": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "gnutls-bin",
            "binary_version": "3.7.3-4ubuntu1.9"
          },
          {
            "binary_name": "guile-gnutls",
            "binary_version": "3.7.3-4ubuntu1.9"
          },
          {
            "binary_name": "libgnutls-dane0",
            "binary_version": "3.7.3-4ubuntu1.9"
          },
          {
            "binary_name": "libgnutls-openssl27",
            "binary_version": "3.7.3-4ubuntu1.9"
          },
          {
            "binary_name": "libgnutls30",
            "binary_version": "3.7.3-4ubuntu1.9"
          },
          {
            "binary_name": "libgnutlsxx28",
            "binary_version": "3.7.3-4ubuntu1.9"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "gnutls28",
        "purl": "pkg:deb/ubuntu/gnutls28@3.7.3-4ubuntu1.9?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.7.3-4ubuntu1.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.7.1-5ubuntu1",
        "3.7.2-2ubuntu1",
        "3.7.2-4ubuntu1",
        "3.7.2-5ubuntu1",
        "3.7.3-4ubuntu1",
        "3.7.3-4ubuntu1.1",
        "3.7.3-4ubuntu1.2",
        "3.7.3-4ubuntu1.3",
        "3.7.3-4ubuntu1.4",
        "3.7.3-4ubuntu1.5",
        "3.7.3-4ubuntu1.6",
        "3.7.3-4ubuntu1.7",
        "3.7.3-4ubuntu1.8"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "gnutls-bin",
            "binary_version": "3.7.3-4ubuntu1.2+Fips1.1"
          },
          {
            "binary_name": "guile-gnutls",
            "binary_version": "3.7.3-4ubuntu1.2+Fips1.1"
          },
          {
            "binary_name": "libgnutls-dane0",
            "binary_version": "3.7.3-4ubuntu1.2+Fips1.1"
          },
          {
            "binary_name": "libgnutls-openssl27",
            "binary_version": "3.7.3-4ubuntu1.2+Fips1.1"
          },
          {
            "binary_name": "libgnutls30",
            "binary_version": "3.7.3-4ubuntu1.2+Fips1.1"
          },
          {
            "binary_name": "libgnutlsxx28",
            "binary_version": "3.7.3-4ubuntu1.2+Fips1.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:FIPS-preview:22.04:LTS",
        "name": "gnutls28",
        "purl": "pkg:deb/ubuntu/gnutls28@3.7.3-4ubuntu1.2+Fips1.1?arch=source\u0026distro=fips-preview/jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.7.3-4ubuntu1.2+Fips1.1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "gnutls-bin",
            "binary_version": "3.7.3-4ubuntu1.9+Fips1"
          },
          {
            "binary_name": "guile-gnutls",
            "binary_version": "3.7.3-4ubuntu1.9+Fips1"
          },
          {
            "binary_name": "libgnutls-dane0",
            "binary_version": "3.7.3-4ubuntu1.9+Fips1"
          },
          {
            "binary_name": "libgnutls-openssl27",
            "binary_version": "3.7.3-4ubuntu1.9+Fips1"
          },
          {
            "binary_name": "libgnutls30",
            "binary_version": "3.7.3-4ubuntu1.9+Fips1"
          },
          {
            "binary_name": "libgnutlsxx28",
            "binary_version": "3.7.3-4ubuntu1.9+Fips1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:FIPS-updates:22.04:LTS",
        "name": "gnutls28",
        "purl": "pkg:deb/ubuntu/gnutls28@3.7.3-4ubuntu1.9+Fips1?arch=source\u0026distro=fips-updates/jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.7.3-4ubuntu1.9+Fips1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.7.3-4ubuntu1.2+Fips1.1",
        "3.7.3-4ubuntu1.3+Fips1.1",
        "3.7.3-4ubuntu1.4+Fips1",
        "3.7.3-4ubuntu1.5+Fips1",
        "3.7.3-4ubuntu1.6+Fips1",
        "3.7.3-4ubuntu1.7+Fips1",
        "3.7.3-4ubuntu1.7+Fips1.1",
        "3.7.3-4ubuntu1.8+Fips1.1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "gnutls-bin",
            "binary_version": "3.8.3-1.1ubuntu3.6"
          },
          {
            "binary_name": "libgnutls-dane0t64",
            "binary_version": "3.8.3-1.1ubuntu3.6"
          },
          {
            "binary_name": "libgnutls-openssl27t64",
            "binary_version": "3.8.3-1.1ubuntu3.6"
          },
          {
            "binary_name": "libgnutls30t64",
            "binary_version": "3.8.3-1.1ubuntu3.6"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "gnutls28",
        "purl": "pkg:deb/ubuntu/gnutls28@3.8.3-1.1ubuntu3.6?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.8.3-1.1ubuntu3.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.8.1-4ubuntu1",
        "3.8.1-4ubuntu6",
        "3.8.1-4ubuntu7",
        "3.8.3-1ubuntu1",
        "3.8.3-1.1ubuntu2",
        "3.8.3-1.1ubuntu3",
        "3.8.3-1.1ubuntu3.1",
        "3.8.3-1.1ubuntu3.2",
        "3.8.3-1.1ubuntu3.3",
        "3.8.3-1.1ubuntu3.4",
        "3.8.3-1.1ubuntu3.5"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "gnutls-bin",
            "binary_version": "3.8.3-1.1ubuntu3.6+Fips1.2"
          },
          {
            "binary_name": "libgnutls-dane0t64",
            "binary_version": "3.8.3-1.1ubuntu3.6+Fips1.2"
          },
          {
            "binary_name": "libgnutls-openssl27t64",
            "binary_version": "3.8.3-1.1ubuntu3.6+Fips1.2"
          },
          {
            "binary_name": "libgnutls30t64",
            "binary_version": "3.8.3-1.1ubuntu3.6+Fips1.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:FIPS-updates:24.04:LTS",
        "name": "gnutls28",
        "purl": "pkg:deb/ubuntu/gnutls28@3.8.3-1.1ubuntu3.6+Fips1.2?arch=source\u0026distro=fips-updates/noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.8.3-1.1ubuntu3.6+Fips1.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.8.3-1.1ubuntu3.1+Fips1",
        "3.8.3-1.1ubuntu3.4+Fips1",
        "3.8.3-1.1ubuntu3.4+Fips1.1",
        "3.8.3-1.1ubuntu3.5+Fips1.1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "gnutls-bin",
            "binary_version": "3.8.9-3ubuntu2.2"
          },
          {
            "binary_name": "libgnutls-dane0t64",
            "binary_version": "3.8.9-3ubuntu2.2"
          },
          {
            "binary_name": "libgnutls-openssl27t64",
            "binary_version": "3.8.9-3ubuntu2.2"
          },
          {
            "binary_name": "libgnutls30t64",
            "binary_version": "3.8.9-3ubuntu2.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "gnutls28",
        "purl": "pkg:deb/ubuntu/gnutls28@3.8.9-3ubuntu2.2?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.8.9-3ubuntu2.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.8.9-2ubuntu3",
        "3.8.9-3ubuntu1",
        "3.8.9-3ubuntu2",
        "3.8.9-3ubuntu2.1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "gnutls-bin",
            "binary_version": "3.8.12-2ubuntu1.1"
          },
          {
            "binary_name": "libgnutls-dane0t64",
            "binary_version": "3.8.12-2ubuntu1.1"
          },
          {
            "binary_name": "libgnutls-openssl27t64",
            "binary_version": "3.8.12-2ubuntu1.1"
          },
          {
            "binary_name": "libgnutls30t64",
            "binary_version": "3.8.12-2ubuntu1.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "gnutls28",
        "purl": "pkg:deb/ubuntu/gnutls28@3.8.12-2ubuntu1.1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.8.12-2ubuntu1.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.8.9-3ubuntu2",
        "3.8.10-3ubuntu1",
        "3.8.12-2ubuntu1"
      ]
    }
  ],
  "aliases": [],
  "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.",
  "id": "UBUNTU-CVE-2026-42011",
  "modified": "2026-07-06T14:11:22Z",
  "published": "2026-05-07T15:16:00Z",
  "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"
    }
  ],
  "related": [
    "USN-8284-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-42011"
  ]
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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