{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "last_affected": "0"
              }
            ],
            "source": "AFFECTED_FIELD"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "0"
            }
          ],
          "repo": "https://gitlab.com/gnutls/gnutls",
          "type": "GIT"
        }
      ],
      "versions": [
        "0"
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "redhat",
    "cwe_ids": [
      "CWE-295"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42013.json"
  },
  "details": "A flaw was found in gnutls. When validating certificates, an oversized Subject Alternative Name (SAN) could cause the validation process to incorrectly fall back to checking the Common Name (CN) field. This could allow a remote attacker to bypass proper certificate validation, potentially leading to spoofing or man-in-the-middle attacks.",
  "id": "CVE-2026-42013",
  "modified": "2026-10-11T02:30:37.074772391Z",
  "published": "2026-05-26T21:29:32.887Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://access.redhat.com/downloads/content/package-browser/"
    },
    {
      "type": "WEB",
      "url": "https://catalog.redhat.com/software/containers/"
    },
    {
      "type": "WEB",
      "url": "https://www.gnutls.org/security-new.html#GNUTLS-SA-2026-04-29-8"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:13274"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:20611"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:20612"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:20613"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:26319"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:26409"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:29197"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:30004"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:30849"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:30850"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:32962"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:33125"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:40762"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:41921"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:43575"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:56853"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:57483"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:58981"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:59831"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:60019"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:72502"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:74674"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/security/cve/CVE-2026-42013"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42013.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42013"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2467448"
    },
    {
      "type": "PACKAGE",
      "url": "https://gitlab.com/gnutls/gnutls"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Gnutls: gnutls: certificate validation bypass due to oversized subject alternative name"
}