How severe is CVE-2021-32721?

CVE-2021-32721 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-32721?

CVE-2021-32721 affects the following packages: github.com/AndrewBurian/powermux (Go). Ecosystems affected: Go.

How do I fix CVE-2021-32721?

Update github.com/AndrewBurian/powermux to 1.1.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-32721 is resolved across your whole dependency graph.

How do I detect CVE-2021-32721 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/AndrewBurian/powermux, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-32721 if there is no patch (or I can't update yet)?

Stop reflecting attacker-controlled destinations: resolve every redirect target against an allowlist of paths or hosts you own, prefer a server-side key over a full URL in the request, and reject absolute URLs entirely where the flow only ever needs a relative one.

Is CVE-2021-32721 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-32721 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-32721?

CVE-2021-32721 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 47th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-32721?

CVE-2021-32721 is classified as Open Redirect (CWE-601). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-32721 published, and has it been updated?

CVE-2021-32721 was published on June 29, 2021 and was last updated on July 9, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

CVE-2021-32721 — powermux

MEDIUMFix: AndrewBurian/powermux#42

CVE-2021-32721 is a medium-severity (CVSS 6.1) Open Redirect vulnerability in github.com/AndrewBurian/powermux. A fix is available for github.com/AndrewBurian/powermux — see the affected versions and patch details below.

Open Redirect in github.com/AndrewBurian/powermux

Also known asGHSA-mj9r-wwm8-7q52GO-2021-0237

Published

Jun 29, 2021

Updated

Jul 9, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs47th percentile — riskier than 47% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-32721 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

🐹github.com/AndrewBurian/powermux

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Impact

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.

Patches

The issue is resolved in v1.1.1

Workarounds

There are no existing workarounds. You may detect attempts to craft urls that exploit this feature by looking for request paths containing pairs of forward slashes in sequence combined with a trailing slash e.g. https://example.com//foo/

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/AndrewBurian/powermux`	all versions	1.1.1`go get github.com/AndrewBurian/powermux@v1.1.1`

Affected Products

1 product · 1 configurations

Application

powermuxpowermux_project

< 1.1.1

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/AndrewBurian/powermux, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/AndrewBurian/powermux to 1.1.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-32721 is resolved across your whole dependency graph.
Workarounds
Stop reflecting attacker-controlled destinations: resolve every redirect target against an allowlist of paths or hosts you own, prefer a server-side key over a full URL in the request, and reject absolute URLs entirely where the flow only ever needs a relative one.

Frequently Asked Questions

### Impact 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. ### Patches The issue is resolved in v1.1.1 ### Workarounds There are no existing workarounds. You may detect attempts to craft urls that exploit this feature by looking for request paths containing pairs of forward slashes in sequence combined with a trailing slash e.g. `https://example.com//foo/`