{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2026-07-13T19:30:45.640Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/07/13/5"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "packageName": "perl",
          "product": "perl",
          "programFiles": [
            "regcomp_study.c"
          ],
          "programRoutines": [
            {
              "name": "Perl_study_chunk"
            }
          ],
          "repo": "https://github.com/Perl/perl5",
          "vendor": "SHAY",
          "versions": [
            {
              "lessThanOrEqual": "5.43.9",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Perl versions through 5.43.9 produce silently incorrect regular expression matches when an alternation of more than 65535 fixed string branches is compiled into a trie in Perl_study_chunk.\n\nWhen such branches are combined into a trie, the delta between the first branch and the shared tail is stored in a 16-bit field. A branch count above 65535 overflows the field, and the trie\u0027s match decision table is truncated with no warning or error.\n\nA pattern of this shape produces false positive matches (matching strings it should not) and false negative matches (failing to match strings it should). When such a pattern gates an access or filtering decision, the result is wrong."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-190",
              "description": "CWE-190 Integer Overflow or Wraparound",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-13T15:40:11.035Z",
        "orgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
        "shortName": "CPANSec"
      },
      "references": [
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/Perl/perl5/commit/03f74bbbd3a68350d926ee93d56ee4808c28c4c7.patch"
        },
        {
          "tags": [
            "issue-tracking"
          ],
          "url": "https://github.com/Perl/perl5/issues/23388"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Apply the upstream patch. The fix is included in the Perl 5.43.10 development release."
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Perl versions through 5.43.9 produce silently incorrect regular expression matches when an alternation of more than 65535 fixed string branches is compiled into a trie in Perl_study_chunk",
      "x_generator": {
        "engine": "cpansec-cna-tool 0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
    "assignerShortName": "CPANSec",
    "cveId": "CVE-2026-13221",
    "datePublished": "2026-07-13T15:40:11.035Z",
    "dateReserved": "2026-06-24T15:38:41.010Z",
    "dateUpdated": "2026-07-13T19:30:45.640Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}