CVE-2026-56763 Details
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.
A prototype pollution vulnerability exists in Hono versions prior to 4.12.7. When the parseBody function is used with the dot option enabled, specially crafted form field names can create objects with __proto__ properties. This issue arises because the __proto__ path segment is not properly filtered, allowing the creation of objects that can later be merged into regular JavaScript objects using unsafe patterns, potentially leading to unauthorized modifications of object behavior.
Users can upgrade to Hono version 4.12.7 or later to address this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Jul 11, 2026CISA-ADP
Assessed Jul 14, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-1321 | Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Hono | < 4.12.7 (semver) |
CPE
Remediation
| |
Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 14, 2026 | CVE Modified | CISA-ADP |
| Jul 11, 2026 | New CVE Received | [email protected] |