{"id":"CVE-2026-126356","summary":"Hono: `validator('form')` skips validation for `multipart/form-data` requests with extra parameters","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.","aliases":["GHSA-4h7h-rv7c-7m2v"],"modified":"2026-11-13T10:46:23.785583553Z","published":"2026-11-12T22:16:37.256Z","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"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126356.json"},{"type":"FIX","url":"https://github.com/honojs/hono/commit/d88fab372415277a9e540e895650943dd08eef4a"},{"type":"WEB","url":"https://github.com/honojs/hono/releases/tag/v4.13.16"},{"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"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/honojs/hono","events":[{"introduced":"0535579de5af90319165304be409ea9b7d5d47f3"},{"fixed":"c91b60a251186fb024557c6d55a11d8e388f179c"},{"fixed":"d88fab372415277a9e540e895650943dd08eef4a"}],"database_specific":{"extracted_events":[{"source":"AFFECTED_FIELD","strategy":"StringRangeExpression","range":[{"introduced":"4.5.1"},{"fixed":"4.13.16"}]},{"range":[{"fixed":"d88fab372415277a9e540e895650943dd08eef4a"}],"source":"REFERENCES_COMMIT"},{"original_tag":"v4.13.16","range":[{"fixed":"c91b60a251186fb024557c6d55a11d8e388f179c"}],"source":"REFERENCES_TAG"}]}}],"versions":["v4.13.15","v4.13.14","@hono/vercel@1.0.1","@hono/service-worker@1.0.1","@hono/netlify@1.0.2","@hono/lambda-edge@1.0.1","@hono/deno@1.0.3","@hono/cloudflare-workers@1.0.1","@hono/bun@1.0.1","@hono/aws-lambda@1.0.1","v4.13.13","v4.13.12","v4.13.11","@hono/netlify@1.0.1","@hono/deno@1.0.2","@hono/deno@1.0.1","v4.13.10","v4.13.9","v4.13.8","v4.13.7","v4.13.6","v4.13.5","v4.13.4","v4.13.3","v4.13.2","v4.13.1","v4.13.0","v4.12.34","v4.12.33","v4.12.32","v4.12.31","v4.12.30","v4.12.29","v4.12.28","v4.12.27","v4.12.26","v4.12.25","v4.12.24","v4.12.23","v4.12.22","v4.12.21","v4.12.20","v4.12.19","v4.12.18","v4.12.17","v4.12.16","v4.12.15","v4.12.14","v4.12.13","v4.12.12","v4.12.11","v4.12.10","v4.12.9","v4.12.8","v4.12.7","v4.12.6","v4.12.5","v4.12.4","v4.12.3","v4.12.2","v4.12.1","v4.12.0","v4.11.10","v4.11.9","v4.11.8","v4.11.7","v4.11.6","v4.11.5","v4.11.4","v4.11.3","v4.11.2","v4.11.1","v4.11.0","v4.10.8","v4.10.7","v4.10.6","v4.10.5","v4.10.4","v4.10.3","v4.10.2","v4.10.1","v4.10.0","v4.9.12","v4.9.11","v4.9.10","v4.9.9","v4.9.8","v4.9.7","v4.9.6","v4.9.5","v4.9.4","v4.9.3","v4.9.2","v4.9.1","v4.9.0","v4.8.12","v4.8.11","v4.8.10","v4.8.9","v4.8.8","v4.8.7","v4.8.6","v4.8.5","v4.8.4","v4.8.3","v4.8.2","v4.8.1","v4.8.0","v4.7.11","v4.7.10","v4.7.9","v4.7.8","v4.7.7","v4.7.6","v4.7.5","v4.7.4","v4.7.3","v4.7.2","v4.7.1","v4.7.0","v4.6.20","v4.6.19","v4.6.18","v4.6.17","v4.6.16","v4.6.15","v4.6.14","v4.6.13","v4.6.12","v4.6.11","v4.6.10","v4.6.9","v4.6.8","v4.6.7","v4.6.6","v4.6.5","v4.6.4","v4.6.3","v4.6.2","v4.6.1","v4.6.0","v4.5.11","v4.5.10","v4.5.9","v4.5.8","v4.5.7","v4.5.6","v4.5.5","v4.5.4","v4.5.3","v4.5.2","v4.5.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-126356.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"}]}