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CVE-2026-9495

Published: May 26, 2026

Modified: May 26, 2026

PUBLISHED

CVSS v3.1

7.3

HIGH

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.

Vendor	Product	Versions
n/a	@koa/router	affected `14.0.0 - < 15.0.0`

Weaknesses (CWE)

CVSS v3.1 Details

CVSS v3.1 Vector

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

Low

References

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

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

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

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

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