---
id: CVE-2026-84363
title: >-
  Hono is a Web application framework that provides support for any JavaScript
  runtime
summary: >-
  Hono is a Web application framework that provides support for any JavaScript
  runtime. Prior to 4.13.5, Hono's query helpers treat a question mark after a
  literal hash fragment as the start of a query string, so the application can
  read r…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N'
cwe:
  - CWE-444
vendor: hono
product: hono
affected:
  - hono < 4.13.5
patched:
  - hono 4.13.5
published: '2026-09-01'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T21:09:13.080'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-84363'
references:
  - url: >-
      https://github.com/honojs/hono/commit/9c28d724c5a7fb086ebaa812fdc1ad6e957c63bc
    label: security-advisories@github.com
  - url: 'https://github.com/honojs/hono/releases/tag/v4.13.5'
    label: security-advisories@github.com
  - url: 'https://github.com/honojs/hono/security/advisories/GHSA-crvj-82cr-hjcx'
    label: security-advisories@github.com
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-84363'
  - url: 'https://github.com/advisories/GHSA-crvj-82cr-hjcx'
tags:
  - nvd
  - ghsa
  - npm
epss: 0.00448
epssPercentile: 0.3632
aliases:
  - GHSA-crvj-82cr-hjcx
ecosystem: npm
ingestedAt: '2026-09-08T22:12:30.968Z'
---

## Overview

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.13.5, Hono's query helpers treat a question mark after a literal hash fragment as the start of a query string, so the application can read request parameters that browsers, new URL(), reverse proxies, filtering rules, parameter allow and deny lists, access logging, request validation, and other middleware do not observe. The Cache Middleware removes the fragment when building its cache key, allowing a response influenced by parameters inside the fragment to be stored under a key that omits those parameters and later served to other users. This can bypass filtering and auditing, poison cached responses, and enable stored cross-site scripting when an affected parameter is reflected into cached HTML without escaping. Exploitation requires a runtime and intermediary path that passes a literal hash character through to the request URL; Cloudflare Workers and intermediaries that strip fragments are not affected. This issue is fixed in version 4.13.5.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-84363)

Affected packages:

- `hono < 4.13.5`

Patched in:

- `hono 4.13.5`

Source: https://github.com/advisories/GHSA-crvj-82cr-hjcx