CVE-2021-23387: Trailing-Slash Project Trailing-Slash

Medium severity, CVSS 6.1. EPSS: 1.2% chance of exploitation in the next 30 days.

The package trailing-slash before 2.0.1 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::createTrailing(), as the web server uses relative URLs instead of absolute URLs.

Affected products

• Trailing-Slash Project Trailing-Slash: before 2.0.1 (fixed in 2.0.1)

Published 2021-05-24. Last modified 2026-06-17.