MIME::Field::ParamVal versions before 5.521 for Perl do not flag a duplicate boundary parameter whose name contains a nested comment

{
  "id": "25f83e8f31dd0db43d09927a7203300a87719a1080fdcfc758bbc1015098d1cf",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-116272",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "MIME::Field::ParamVal versions before 5.521 for Perl do not flag a duplicate boundary parameter whose name contains a nested comment",
    "summary": "MIME::Field::ParamVal versions before 5.521 for Perl do not flag a duplicate boundary parameter whose name contains a nested comment. A parameter written boundary((c))=\"A\" or boundary(\\))=\"A\" is stored under that literal name rather than as boundary. A second boundary parameter is then not reported as a duplicate, and MIME::Parser splits the message on it. Readers that skip comments as RFC 5322 allows take the first boundary instead. A remote sender can hide an attachment from a filter that relies on ambiguous_content() while the recipient's mail client shows it.",
    "evidence": "cve:CVE-2026-116272",
    "products": [],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-116272",
      "aliases": [
        "CVE-2026-116272"
      ],
      "metrics": [],
      "affected": [
        {
          "repo": "https://salsa.debian.org/dskoll/mime-tools",
          "modules": [
            "MIME::Field::ParamVal"
          ],
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "lessThan": "5.521",
              "versionType": "custom"
            }
          ],
          "packageURL": "pkg:cpan/MIME-tools",
          "packageName": "MIME-tools",
          "programFiles": [
            "lib/MIME/Field/ParamVal.pm"
          ],
          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "programRoutines": [
            {
              "name": "MIME::Field::ParamVal::parse_params"
            }
          ]
        }
      ],
      "modified": "2026-10-28T17:34:25.862Z",
      "provider": "cve",
      "references": [
        "https://metacpan.org/release/DSKOLL/MIME-tools-5.521/changes"
      ],
      "provider_metadata": {
        "cna": {
          "orgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
          "shortName": "CPANSec",
          "dateUpdated": "2026-10-28T17:34:25.862Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-116272",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-cve",
  "document_id": 466448,
  "published_at": "2026-10-28T17:34:25.862+00:00"
}