CVE-2026-9495CWE-284

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…

Medium · published May 26, 2026

CVSS v4.0
6.9
EPSS
1%
Percentile
48.6
In the wild
Unconfirmed
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.

The record
Technical detail
CVSS v4.0
6.9 · MEDIUM
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
EPSS
0.00611 · 48.6th percentile
Weakness
CWE-284 · Improper Access Control
Published
2026-05-26T05:00Z
EPSS history
Timeline
  • 26 MAY 05:00Z
    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…
    cvelistv5