CVE-2026-9495

What it is

Versions of the package @koa/router from 14.0.0 and before 15.0.0 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.

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-05-26 07:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-07-23 11:10 UTC Last updatedMost recent change to the record

Details

Published

2026-05-26 07:16 UTC

Last modified

2026-07-23 11:10 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-284 · Improper access control

Record status

Awaiting Analysis

Attack profile CVSS 4.0 · 5.5

Attack vector

Network

Complexity

Low

Attack requirements

None

Privileges needed

None

User interaction

None

Confidentiality

Low

Integrity

Low

Availability

Low