CVE-2026-56763

medium

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.

References

https://www.vulncheck.com/advisories/hono-prototype-pollution-via-proto-key-in-parsebody-with-dot-option

https://github.com/honojs/hono/security/advisories/GHSA-v8w9-8mx6-g223

Details

Source: Mitre, NVD

Published: 2026-07-11

Updated: 2026-07-11

Risk Information

CVSS v2

Base Score: 4

Vector: CVSS2#AV:N/AC:H/Au:N/C:P/I:P/A:N

Severity: Medium

CVSS v3

Base Score: 4.8

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

Severity: Medium

CVSS v4

Base 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

Severity: Medium