CVE-2026-56763
Hono - Prototype Pollution via __proto__ Key in parseBody with dot Option
- State
- Published
- Severity
- 6.3 Medium
- Published
- Jul 11, 2026
- Updated
- Jul 14, 2026
- Reserved
- Jun 22, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.3 Medium | 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 | VulnCheck |
| 3.1 | 4.8 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N | VulnCheck |
Weaknesses
- CWE-1321 Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Affected Products
| Product | Versions |
|---|---|
HonoHono |
|
References
- GitHub Security Advisory (GHSA-v8w9-8mx6-g223)vendor-advisory
- VulnCheck Advisory: Hono - Prototype Pollution via __proto__ Key in parseBody with dot Optionthird-party-advisory
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