Fix CVE(s): CVE-2026-42011, CVE-2026-42012, CVE-2026-42013

{
  "id": "3ce3b87aa6682a43f15dff30d16d20ddd66efda27a511292c1640ba98ff8e4ec",
  "url": "https://osv.dev/vulnerability/CLSA-2026-1784559374",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Fix CVE(s): CVE-2026-42011, CVE-2026-42012, CVE-2026-42013",
    "summary": "* SECURITY UPDATE: Name constraints bypass when prior CAs have only excluded constraints - debian/patches/CVE-2026-42011.patch: remove the empty-permitted early return in name_constraints_node_list_intersect in lib/x509/name_constraints.c so permitted name constraints of a subsequent CA still propagate when previous CAs only carried excluded constraints; also backport the upstream regression suites to tests/name-constraints-merge.c - CVE-2026-42011 * SECURITY UPDATE: Certificate validation bypass via oversized subject alternative name - debian/patches/CVE-2026-42013.patch: refactor the CN and DN-email fallback logic and disable the fallback when gnutls_x509_crt_get_subject_alt_name reports an oversized SAN (GNUTLS_E_SHORT_MEMORY_BUFFER) in gnutls_x509_crt_check_hostname2 and gnutls_x509_crt_check_email (lib/x509/hostname-verify.c, lib/x509/email-verify.c); also backport the upstream regression tests to tests/hostname-check.c and tests/cert-tests/email (with tests/cert-tests/email-certs/oversized-san.pem) - CVE-2026-42013 * SECURITY UPDATE: CN fallback not precluded by URI or SRV subject alternative names - debian/patches/CVE-2026-42012.patch: add GNUTLS_SAN_URI and GNUTLS_SAN_OTHERNAME_SRV to the PRECLUDES_CN_FALLBACK macro in lib/x509/hostname-verify.c so certificates presenting URI or SRV SANs no longer allow hostname matching against the common name per RFC 6125 6.4.4; backport SRV virtual-SAN awareness (lib/includes/gnutls/gnutls.h.in, lib/x509/common.h, lib/x509/virt-san",
    "evidence": "osv:CLSA-2026-1784559374",
    "products": [
      {
        "name": {
          "value": "gnutls-bin",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "3.6.13-2ubuntu1.12+tuxcare.els6",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "gnutls-doc",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "3.6.13-2ubuntu1.12+tuxcare.els6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "guile-gnutls",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "3.6.13-2ubuntu1.12+tuxcare.els6",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "libgnutls-dane0",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "3.6.13-2ubuntu1.12+tuxcare.els6",
            "evidence": "/affected/3/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "libgnutls-openssl27",
          "evidence": "/affected/4/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "3.6.13-2ubuntu1.12+tuxcare.els6",
            "evidence": "/affected/4/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "libgnutls28-dev",
          "evidence": "/affected/5/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "3.6.13-2ubuntu1.12+tuxcare.els6",
            "evidence": "/affected/5/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "libgnutls30",
          "evidence": "/affected/6/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "3.6.13-2ubuntu1.12+tuxcare.els6",
            "evidence": "/affected/6/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "libgnutlsxx28",
          "evidence": "/affected/7/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "3.6.13-2ubuntu1.12+tuxcare.els6",
            "evidence": "/affected/7/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CLSA-2026-1784559374",
      "aliases": [
        "CLSA-2026-1784559374"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "3.6.13-2ubuntu1.12+tuxcare.els6"
                }
              ]
            }
          ],
          "package": {
            "name": "gnutls-bin",
            "purl": "pkg:deb/tuxcare/gnutls-bin?distro=ubuntu-20.04",
            "ecosystem": "TuxCare:Ubuntu:20.04"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu20.04els/CLSA-2026-1784559374.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "3.6.13-2ubuntu1.12+tuxcare.els6"
                }
              ]
            }
          ],
          "package": {
            "name": "gnutls-doc",
            "purl": "pkg:deb/tuxcare/gnutls-doc?distro=ubuntu-20.04",
            "ecosystem": "TuxCare:Ubuntu:20.04"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu20.04els/CLSA-2026-1784559374.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "3.6.13-2ubuntu1.12+tuxcare.els6"
                }
              ]
            }
          ],
          "package": {
            "name": "guile-gnutls",
            "purl": "pkg:deb/tuxcare/guile-gnutls?distro=ubuntu-20.04",
            "ecosystem": "TuxCare:Ubuntu:20.04"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu20.04els/CLSA-2026-1784559374.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "3.6.13-2ubuntu1.12+tuxcare.els6"
                }
              ]
            }
          ],
          "package": {
            "name": "libgnutls-dane0",
            "purl": "pkg:deb/tuxcare/libgnutls-dane0?distro=ubuntu-20.04",
            "ecosystem": "TuxCare:Ubuntu:20.04"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu20.04els/CLSA-2026-1784559374.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "3.6.13-2ubuntu1.12+tuxcare.els6"
                }
              ]
            }
          ],
          "package": {
            "name": "libgnutls-openssl27",
            "purl": "pkg:deb/tuxcare/libgnutls-openssl27?distro=ubuntu-20.04",
            "ecosystem": "TuxCare:Ubuntu:20.04"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu20.04els/CLSA-2026-1784559374.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "3.6.13-2ubuntu1.12+tuxcare.els6"
                }
              ]
            }
          ],
          "package": {
            "name": "libgnutls28-dev",
            "purl": "pkg:deb/tuxcare/libgnutls28-dev?distro=ubuntu-20.04",
            "ecosystem": "TuxCare:Ubuntu:20.04"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu20.04els/CLSA-2026-1784559374.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "3.6.13-2ubuntu1.12+tuxcare.els6"
                }
              ]
            }
          ],
          "package": {
            "name": "libgnutls30",
            "purl": "pkg:deb/tuxcare/libgnutls30?distro=ubuntu-20.04",
            "ecosystem": "TuxCare:Ubuntu:20.04"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu20.04els/CLSA-2026-1784559374.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "3.6.13-2ubuntu1.12+tuxcare.els6"
                }
              ]
            }
          ],
          "package": {
            "name": "libgnutlsxx28",
            "purl": "pkg:deb/tuxcare/libgnutlsxx28?distro=ubuntu-20.04",
            "ecosystem": "TuxCare:Ubuntu:20.04"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu20.04els/CLSA-2026-1784559374.json"
          }
        }
      ],
      "modified": "2026-10-26T09:32:05.529947923Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-42011",
        "CVE-2026-42012",
        "CVE-2026-42013"
      ],
      "references": [
        "https://errata.tuxcare.com/els_os/ubuntu20.04els/CLSA-2026-1784559374.html",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-42011",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-42012",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-42013"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-42011",
        "evidence": "/upstream"
      },
      {
        "value": "CVE-2026-42012",
        "evidence": "/upstream"
      },
      {
        "value": "CVE-2026-42013",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 449690,
  "published_at": "2026-07-20T14:56:45+00:00"
}