---
id: CVE-2026-69207
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 4.12.34, the built-in CORS middleware, hono/cors, is
  vulnerable to a regular expression denial of service (ReDoS). During a
  preflight OPTIONS …
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
cwe:
  - CWE-1333
vendor: hono
product: hono
affected:
  - hono < 4.12.34
patched:
  - hono 4.12.34
published: '2026-08-07'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T21:02:22.660'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-69207'
references:
  - url: >-
      https://github.com/honojs/hono/commit/93fc250d8b4df58ea542cb945171de8013d5e6d5
    label: security-advisories@github.com
  - url: 'https://github.com/honojs/hono/releases/tag/v4.12.34'
    label: security-advisories@github.com
  - url: 'https://github.com/honojs/hono/security/advisories/GHSA-8j4g-w8fx-2239'
    label: security-advisories@github.com
  - url: 'https://github.com/advisories/GHSA-8j4g-w8fx-2239'
tags:
  - nvd
  - ghsa
  - npm
epss: 0.00488
epssPercentile: 0.41136
aliases:
  - GHSA-8j4g-w8fx-2239
ecosystem: npm
ingestedAt: '2026-08-03T20:29:32.217Z'
---

## Overview

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.34, the built-in CORS middleware, hono/cors, is vulnerable to a regular expression denial of service (ReDoS). During a preflight OPTIONS request, the middleware parses the attacker-controlled Access-Control-Request-Headers header using a whitespace-tolerant regular expression whose backtracking makes its running time quadratic in the input length. Because the header value is bounded only by the deployment's maximum HTTP header size, a single preflight carrying a long run of whitespace can consume seconds of CPU and block request processing. On runtimes that share one execution thread across requests, this stalls concurrent requests as well, and repeated requests can render the service unresponsive. This affects the default configuration, since the vulnerable path is reached whenever cors() is used with an unset or empty allowHeaders. Applications that set a non-empty allowHeaders are not affected. This issue is fixed in version 4.12.34.

## Remediation

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

## Package advisory (CVE-2026-69207)

Affected packages:

- `hono < 4.12.34`

Patched in:

- `hono 4.12.34`

Source: https://github.com/advisories/GHSA-8j4g-w8fx-2239