CVE-2021-32721
URL Redirection to Untrusted Site ('Open Redirect') in github.com/AndrewBurian/powermux
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
URL Redirection to Untrusted Site ('Open Redirect') in github.com/AndrewBurian/powermux
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.
- Record
CVE-2021-32721- CVSS 3.1
- 4.7 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-601
- Updated
- 2026-11-02
EUVDEUVD-2021-1482
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.
- Record
EUVD-2021-1482- CVSS 3.1
- 4.7 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-mj9r-wwm8-7q52
Open Redirect in github.com/AndrewBurian/powermux
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/
- Record
GHSA-mj9r-wwm8-7q52- CVSS 3.1
- 4.7 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-601
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2021-32721- CVSS 3.1
- 4.7 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N - CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - CVSS 2.0
- 5.8 Medium
AV:N/AC:M/Au:N/C:P/I:P/A:N - Weakness
- CWE-601
- Updated
- 2026-11-02
OSV
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.
- Record
CVE-2021-32721- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-mj9r-wwm8-7q52
Open Redirect in github.com/AndrewBurian/powermux
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/
- Record
GHSA-mj9r-wwm8-7q52- CVSS 3.1
- 4.7 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-601
- Updated
- 2026-11-02
OSVGO-2021-0237 No score
Open redirect in github.com/AndrewBurian/powermux
Attackers may be able to craft phishing links and other open redirects by exploiting PowerMux's trailing slash redirection feature. This may lead to users being redirected to untrusted sites after following an attacker crafted link.
- Record
GO-2021-0237- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/AndrewBurian/powermuxGo |
before 1.1.1 | 1.1.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-32721 is a medium vulnerability (CVSS 4.7) in Andrewburian Powermux, published June 29, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.61%, the 49th percentile. Fixed in github.com/AndrewBurian/powermux 1.1.1.