PatchTheCVECVE-2021-23387: The package trailing-slash before 2.0.1 are vulnerable to Open Redirect via the use of trailing double slashes
CVE-2021-23387 is a medium-severity flaw (CVSS 5.4) affecting trailing-slash. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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.
Why this priority
- Public exploit reference
A fixed release or distro patch exists.
Risk facts
| CVSS score | 5.4 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | Required |
| EPSS exploit chance | 1.1% (top 33%) |
| CISA exploited list | No |
| Weakness | CWE-601 |
| Published | 2021-05-24 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2021-23387?
trailing-slash: upgrade to 2.0.1. Exact commands for each OS are on this page.
Is CVE-2021-23387 being exploited?
CVE-2021-23387 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2021-23387 affect?
CVE-2021-23387 affects trailing-slash. Severity is medium (CVSS 5.4). 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 ind
How urgent is CVE-2021-23387?
Priority 41/100. Public exploit reference