CVE-2021-23384: Koa-Remove-Trailing-Slashes Project Koa-Remove-Trailing-Slashes

Medium severity, CVSS 5.4. EPSS: 0.8% chance of exploitation in the next 30 days.

The package koa-remove-trailing-slashes before 2.0.2 are vulnerable to Open Redirect via the use of trailing double slashes in the URL when accessing the vulnerable endpoint (such as https://example.com//attacker.example/). The vulnerable code is in index.js::removeTrailingSlashes(), as the web server uses relative URLs instead of absolute URLs.

Affected products

• Koa-Remove-Trailing-Slashes Project Koa-Remove-Trailing-Slashes: before 2.0.2 (fixed in 2.0.2)

Published 2021-05-17. Last modified 2026-06-17.