Hono: `validator('form')` skips validation for `multipart/form-data` requests with extra parameters

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-126356
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-13 00:20:10 UTC
Updated2026-11-13 00:20:10 UTC
DescriptionHono 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.

Risk And Classification

Primary CVSS: v3.1 5.3 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Problem Types: CWE-20 | CWE-20 CWE-20: Improper Input Validation | CWE-1471 CWE-1471: Insufficiently Controlled Parser Differential

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
3.1CNADECLARED5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Honojs Hono affected >= 4.5.1, < 4.13.16 Not specified

References

ReferenceSourceLinkTags
github.com/honojs/hono/releases/tag/v4.13.16 [email protected] github.com
github.com/honojs/hono/security/advisories/GHSA-4h7h-rv7c-7m2v [email protected] github.com
github.com/honojs/hono/commit/d88fab372415277a9e540e895650943dd08eef4a [email protected] github.com
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