---
id: GHSA-3wcj-gjvf-fvch
title: >-
  Duplicate Advisory: Hono vulnerable to Prototype Pollution possible through
  __proto__ key allowed in parseBody({ dot: true })
summary: >-
  Duplicate Advisory: Hono vulnerable to Prototype Pollution possible through
  __proto__ key allowed in parseBody({ dot: true })
severity: medium
cvss: 4.8
cwe:
  - CWE-1321
vendor: hono
product: hono
ecosystem: npm
affected:
  - hono < 4.12.7
published: '2026-07-11'
updated: '2026-10-02'
sourceUpdated: '2026-10-02T22:36:00Z'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-3wcj-gjvf-fvch'
references:
  - url: 'https://github.com/honojs/hono/security/advisories/GHSA-v8w9-8mx6-g223'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-56763'
  - url: >-
      https://www.vulncheck.com/advisories/hono-prototype-pollution-via-proto-key-in-parsebody-with-dot-option
  - url: 'https://github.com/advisories/GHSA-3wcj-gjvf-fvch'
tags:
  - ghsa
  - npm
ingestedAt: '2026-10-02T23:34:57.406Z'
---

## Overview

## Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-v8w9-8mx6-g223. This link is maintained to preserve external references.

## Original 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.

## Affected packages

- `hono < 4.12.7`

## Remediation

Refer to the advisory for the patched release.