CVE-2026-56763

Hono - Prototype Pollution via __proto__ Key in parseBody with dot Option

Published Jul 11, 2026 CVSS 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed
Description
Hono before 4.12.7 allows __proto__ key in parseBody with dot option enabled, permitting specially crafted form field names to create objects with __proto__ properties. When parsed results are merged into regular JavaScript objects using unsafe merge patterns, attackers can exploit this to achieve prototype pollution and modify object behavior.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Github GHSA Github GHSA GHSA-v8w9-8mx6-g223 Hono vulnerable to Prototype Pollution possible through __proto__ key allowed in parseBody({ dot: true })
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Hono before 4.12.7 allows __proto__ key in parseBody with dot option enabled, permitting specially crafted form field names to create objects with __proto__ properties. When parsed results are merged into regular JavaScript objects using unsafe merge patterns, attackers can exploit this to achieve prototype pollution and modify object behavior.
Title Hono - Prototype Pollution via __proto__ Key in parseBody with dot Option
First Time appeared Hono
Hono hono
Weaknesses CWE-1321
CPEs cpe:2.3:a:hono:hono:*:*:*:*:*:node.js:*:*
Vendors & Products Hono
Hono hono
References
Metrics cvssV3_1

{'score': 4.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N'}

cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Jul 14, 2026, 2:30 PM
Reserved
Jun 22, 2026, 9:55 PM
Status
Deferred
Published
Jul 11, 2026, 2:16 PM
Modified
Oct 25, 2026, 3:10 PM