Access Control Bypass Affecting @koa/router package, versions >=14.0.0 <15.0.0
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applicationsSnyk Learn
Learn about Access Control Bypass vulnerabilities in an interactive lesson.
Start learning- Snyk IDSNYK-JS-KOAROUTER-12215044
- published25 May 2026
- disclosed28 Aug 2025
- creditRyan Mitchell
Introduced: 28 Aug 2025
CVE-2026-9495 (opens in a new tab)How to fix?
Upgrade @koa/router to version 15.0.0 or higher.
Overview
@koa/router is a
Affected versions of this package are vulnerable to Access Control Bypass. due to the middleware being silently dropped from the execution chain when the router prefix contains path parameters. Depending on what the skipped middleware was supposed to protect, an attacker could bypass authentication and authorization, evade rate limiting or bypass input sanitization.