CVE-2026-56763
MEDIUMHono - Prototype Pollution via __proto__ Key in parseBody with dot Option
Title source: cnaDescription
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.
References (2)
Core 2
Core References
Vendor Advisory vendor-advisory
GitHub Security Advisory (GHSA-v8w9-8mx6-g223)
https://github.com/honojs/hono/security/advisories/GHSA-v8w9-8mx6-g223
Third Party Advisory third-party-advisory
VulnCheck Advisory: Hono - Prototype Pollution via __proto__ Key in parseBody with dot Option
https://www.vulncheck.com/advisories/hono-prototype-pollution-via-proto-key-in-parsebody-with-dot-option
Scores
CVSS v3
4.8
EPSS
0.0018
EPSS Percentile
7.5%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
partial
Details
CWE
CWE-1321
Status
published
Products (2)
Hono/Hono
< 4.12.7
Hono/Hono
4.12.7
Published
Jul 11, 2026
Tracked Since
Jul 11, 2026