What is CVE-2021-32721?

CVE-2021-32721 is a medium-severity vulnerability in Andrewburian Powermux, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 4.7/10. Published 2021-06-29.

How severe is CVE-2021-32721?

Medium severity. CVSS v3 base score is 4.7 out of 10.

Open Redirect in Andrewburian Powermux

CVE-2021-32721

PowerMux is a drop-in replacement for Go's http.ServeMux. In PowerMux versions prior to 1.1.1, attackers may be able to craft phishing links and other open redirects by exploiting the trailing slash redirection feature. This may lead to users being redirected to untrusted sites after following an attacker crafted link. The issue is resolved in v1.1.1. There are no existing workarounds.

Vulnerability class: Open Redirect

Published 2021-06-29 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.006 (47.0th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 47.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Andrewburian Powermux — versions < 1.1.1
Powermux Project

Weakness classification (CWE)

CWE-601 — URL Redirection to Untrusted Site (Open Redirect)

References

github.com/AndrewBurian/powermux/security/advisories/GHSA-mj9r-wwm8-7q52 (Third Party Advisory)

Frequently asked questions

What is CVE-2021-32721?: CVE-2021-32721 is a medium-severity vulnerability in Andrewburian Powermux, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 4.7/10. Published 2021-06-29.
How severe is CVE-2021-32721?: Medium severity. CVSS v3 base score is 4.7 out of 10.