{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "4.5.1"
                  },
                  {
                    "fixed": "4.13.16"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StringRangeExpression"
              },
              {
                "range": [
                  {
                    "fixed": "d88fab372415277a9e540e895650943dd08eef4a"
                  }
                ],
                "source": "REFERENCES_COMMIT"
              },
              {
                "original_tag": "v4.13.16",
                "range": [
                  {
                    "fixed": "c91b60a251186fb024557c6d55a11d8e388f179c"
                  }
                ],
                "source": "REFERENCES_TAG"
              }
            ]
          },
          "events": [
            {
              "introduced": "0535579de5af90319165304be409ea9b7d5d47f3"
            },
            {
              "fixed": "c91b60a251186fb024557c6d55a11d8e388f179c"
            },
            {
              "fixed": "d88fab372415277a9e540e895650943dd08eef4a"
            }
          ],
          "repo": "https://github.com/honojs/hono",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-4h7h-rv7c-7m2v"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-1471",
      "CWE-20"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126356.json"
  },
  "details": "Hono is a Web application framework that provides support for any JavaScript runtime. From 4.5.1 until 4.13.16, validator('form') uses a strict whole-header pattern that fails to recognize multipart/form-data when its Content-Type includes another legal parameter or extra whitespace after a semicolon. The validation callback receives an empty object even though c.req.parseBody() or c.req.formData() can still parse and expose all submitted fields to the handler. An unauthenticated client can therefore bypass allow-list or required-field checks when the application relies on the form validator and its callback accepts an empty object. application/x-www-form-urlencoded requests are not affected. This issue is fixed in version 4.13.16.",
  "id": "CVE-2026-126356",
  "modified": "2026-11-14T02:30:51.028893036Z",
  "published": "2026-11-12T22:16:37.256Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/honojs/hono/releases/tag/v4.13.16"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126356.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/honojs/hono/security/advisories/GHSA-4h7h-rv7c-7m2v"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-126356"
    },
    {
      "type": "FIX",
      "url": "https://github.com/honojs/hono/commit/d88fab372415277a9e540e895650943dd08eef4a"
    }
  ],
  "schema_version": "1.9.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Hono: `validator('form')` skips validation for `multipart/form-data` requests with extra parameters"
}