CVE-2021-32721: PowerMux is a drop-in replacement for Go's http.ServeMux

Q: How do I fix CVE-2021-32721?

powermux: upgrade to 1.1.1. Exact commands for each OS are on this page.

Q: Is CVE-2021-32721 being exploited?

CVE-2021-32721 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-32721 affect?

CVE-2021-32721 affects powermux. Severity is medium (CVSS 4.7). 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 use

Q: How urgent is CVE-2021-32721?

Priority 29/100. No elevated risk signals yet.

Routine

MEDIUM 4.7UPGRADE

CVE-2021-32721 is a medium-severity flaw (CVSS 4.7) affecting powermux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	4.7 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.6% (top 51%)
CISA exploited list	No
Weakness	CWE-601
Published	2021-06-29
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: powermux project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-06-29 19:15 UTCPublished CVE record published
2026-06-17 03:53 UTCUpdated Record last modified

powermux project powermux UPGRADE

Affected: < 1.1.1

Fixed in: 1.1.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy powermux || rpm -q powermux || powermux --version

2. UPGRADE to 1.1.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade powermux

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade powermux

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
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-2021-32721?

powermux: upgrade to 1.1.1. Exact commands for each OS are on this page.

Is CVE-2021-32721 being exploited?

CVE-2021-32721 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-2021-32721 affect?

CVE-2021-32721 affects powermux. Severity is medium (CVSS 4.7). 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 use

How urgent is CVE-2021-32721?

Priority 29/100. No elevated risk signals yet.

References

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