{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "19.3"
              },
              {
                "fixed": "26.2.5.21"
              },
              {
                "introduced": "27.0"
              },
              {
                "fixed": "27.3.4.12"
              },
              {
                "introduced": "28.0"
              },
              {
                "fixed": "28.5.0.1"
              },
              {
                "introduced": "29.0"
              },
              {
                "fixed": "29.0.1"
              }
            ],
            "source": [
              "CPE_RANGE",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "a748cafdc7063d9f181ba12088db6458793ced2f"
            },
            {
              "fixed": "c9ce879f4ca194adc5393f52b2c4cd57b3c3d89d"
            },
            {
              "introduced": "601a012837ea0a5c8095bf24223132824177124d"
            },
            {
              "fixed": "a2394acad3e3b8fa74d40905cb79bac2ab68258a"
            },
            {
              "introduced": "9e6f6742c4d9e9915ee8af0dcb7d97cf1f836116"
            },
            {
              "fixed": "5770157eabdd4e8b0b83d64fd8b207c0150c2b64"
            },
            {
              "introduced": "550d7b7898706c7822362c42e7b93120c1d1f29a"
            },
            {
              "fixed": "f26c7e590c5d1b3afa0dee38093442df117822e3"
            },
            {
              "fixed": "0769050c69d73762672b0db1347b6993a5b31759"
            },
            {
              "fixed": "21abed64eb2026b5f82f432709e4e932f9be389a"
            },
            {
              "fixed": "fb67c6d1836f51105a96d8b769e71e4215a79457"
            }
          ],
          "repo": "https://github.com/erlang/otp",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-22cw-4ph4-6447"
  ],
  "database_specific": {
    "cna_assigner": "EEF",
    "cwe_ids": [
      "CWE-295",
      "CWE-297"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42790.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "1.4"
          },
          {
            "fixed": "*"
          },
          {
            "introduced": "19.3"
          },
          {
            "fixed": "*"
          },
          {
            "introduced": "b0c245e8132bb13171e277b1af59c0cec00c9459"
          },
          {
            "fixed": "*"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "details": "Improper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_cert and public_key modules) allows a DNS nameConstraints bypass via subject CommonName fallback in TLS hostname verification.\n\nTwo flaws combine to allow a subordinate CA whose DNS nameConstraints are restricted (e.g. permitted;DNS:allowed.example.com) to issue a leaf certificate that an OTP TLS client accepts as a valid identity for an out-of-scope hostname (e.g. victim.example.com):\n\nFirst, pubkey_cert:validate_names/6 in lib/public_key/src/pubkey_cert.erl only checks SAN DNS entries against nameConstraints. Per RFC 5280, a permitted DNS subtree only restricts certificates that contain a DNS-typed name. A leaf with no subjectAltName therefore trivially satisfies any permitted;DNS:... constraint regardless of its subject commonName.\n\nSecond, public_key:pkix_verify_hostname/3 in lib/public_key/src/public_key.erl falls back to the subject commonName when no subjectAltName is present, extracting id-at-commonName attributes as presented IDs and matching them against the reference hostname. The strict pkix_verify_hostname_match_fun(https) matcher does not suppress this fallback.\n\nThe result is that path validation accepts a CN-only leaf under a DNS-constrained intermediate (no SAN means the nameConstraints are not triggered), and hostname verification then accepts it via the CN fallback. The bypass is reachable from stock ssl:connect with verify_peer, a trusted CA, SNI, and the canonical strict https hostname matcher.\n\nThis issue affects OTP from OTP 19.3 before OTP 26.2.5.21, 27.3.4.12, 28.5.0.1, and 29.0.1 corresponding to public_key from 1.4 before 1.15.1.7, 1.17.1.3, 1.20.3.1, and 1.21.1.",
  "id": "CVE-2026-42790",
  "modified": "2026-07-17T03:42:05.876711117Z",
  "published": "2026-05-27T15:09:01.860Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-42790.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-42790"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42790.json"
    },
    {
      "type": "WEB",
      "url": "https://www.erlang.org/doc/system/versions.html#order-of-versions"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:39809"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/security/cve/CVE-2026-42790"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42790.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/erlang/otp/security/advisories/GHSA-22cw-4ph4-6447"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42790"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2482286"
    },
    {
      "type": "FIX",
      "url": "https://github.com/erlang/otp/commit/0769050c69d73762672b0db1347b6993a5b31759"
    },
    {
      "type": "FIX",
      "url": "https://github.com/erlang/otp/commit/21abed64eb2026b5f82f432709e4e932f9be389a"
    },
    {
      "type": "FIX",
      "url": "https://github.com/erlang/otp/commit/fb67c6d1836f51105a96d8b769e71e4215a79457"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/erlang/otp"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "nameConstraints DNS bypass via subject CommonName fallback in public_key hostname verification"
}