Memory limit bypass when parsing MIME headers in net/textproto, mime/multipart

{
  "id": "b6ddf268a107dcf0b6cc13f09b1557b83cfe531c55b59256213deaf82482cc99",
  "url": "https://osv.dev/vulnerability/GO-2026-6608",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Memory limit bypass when parsing MIME headers in net/textproto, mime/multipart",
    "summary": "Parsing a multipart form can bypass memory limits and read an arbitrarily long line into memory when the remaining limit at the start of a part is less than 400 bytes.",
    "evidence": "osv:GO-2026-6608",
    "products": [
      {
        "name": {
          "value": "stdlib",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.26.9",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "1.27.2",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "GO-2026-6608",
      "aliases": [
        "BIT-golang-2026-94440",
        "CVE-2026-94440",
        "GO-2026-6608"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.26.9"
                },
                {
                  "introduced": "1.27.0-0"
                },
                {
                  "fixed": "1.27.2"
                }
              ]
            }
          ],
          "package": {
            "name": "stdlib",
            "purl": "pkg:golang/stdlib",
            "ecosystem": "Go"
          },
          "database_specific": {
            "source": "https://vuln.go.dev/ID/GO-2026-6608.json"
          },
          "ecosystem_specific": {
            "imports": [
              {
                "path": "net/textproto",
                "symbols": [
                  "Reader.ReadContinuedLine",
                  "Reader.ReadContinuedLineBytes",
                  "Reader.ReadMIMEHeader",
                  "Reader.readContinuedLineSlice",
                  "readMIMEHeader"
                ]
              },
              {
                "path": "mime/multipart",
                "symbols": [
                  "Part.populateHeaders",
                  "Reader.NextPart",
                  "Reader.NextRawPart",
                  "Reader.ReadForm",
                  "Reader.readForm"
                ]
              }
            ]
          }
        }
      ],
      "modified": "2026-10-16T09:55:56.456473146Z",
      "provider": "osv",
      "references": [
        "https://go.dev/cl/847307",
        "https://go.dev/issue/81741",
        "https://groups.google.com/g/golang-announce/c/U2fTuyDJznI"
      ],
      "provider_metadata": {
        "url": "https://pkg.go.dev/vuln/GO-2026-6608",
        "review_status": "REVIEWED"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-94440",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 338726,
  "published_at": "2026-10-08T22:31:09+00:00"
}