CVE-2026-9495

medium

Description

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.

References

https://security.snyk.io/vuln/SNYK-JS-KOAROUTER-12215044

https://github.com/koajs/router/pull/206

https://github.com/koajs/router/issues/202

https://github.com/koajs/router/commit/d53e17f284557b1f417946f9807ee52290c3c759

Details

Source: Mitre, NVD

Published: 2026-05-26

Updated: 2026-05-26

Risk Information

CVSS v2

Base Score: 7.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

Severity: High

CVSS v3

Base Score: 7.3

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Severity: High

CVSS v4

Base Score: 6.9

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

Severity: Medium

EPSS

EPSS: 0.00086