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CVE Record

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.

MediumCVSS 4.7Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

PowerMux versions before 1.1.1 can let an attacker craft links that redirect users from a trusted service to an untrusted site. The main business risk is phishing or user trust abuse, not server compromise. The issue requires user interaction and is fixed in version 1.1.1.

Executive priority

Treat as a targeted phishing risk for services using this library. Remediate during normal dependency maintenance unless the affected service is high-trust, customer-facing, or frequently linked externally.

Technical view

CVE-2021-32721 is a CWE-601 open redirect in github.com/AndrewBurian/powermux before 1.1.1, tied to trailing slash redirection behavior. CVSS 3.1 is 4.7: network reachable, unauthenticated, high complexity, user interaction required, changed scope, low confidentiality and integrity impact, no availability impact.

Likely exposure

Exposure is likely limited to Go applications that directly use github.com/AndrewBurian/powermux versions earlier than 1.1.1, especially public HTTP services where users may follow crafted links.

Exploitation context

The provided bundle does not show KEV listing or active exploitation. Abuse would depend on convincing a user to follow a crafted link and on the application exposing affected redirect behavior.

Researcher notes

The source bundle names only AndrewBurian powermux before 1.1.1 as affected. Do not generalize to Go http.ServeMux or unrelated routers without separate evidence. No workaround is documented.

Mitigation direction

  • Upgrade github.com/AndrewBurian/powermux to version 1.1.1 or later.
  • Check the GitHub advisory for any later vendor guidance.
  • Prioritize public routes using PowerMux redirect handling.
  • Do not rely on a workaround; the advisory lists none.

Validation and detection

  • Inventory Go modules for github.com/AndrewBurian/powermux usage.
  • Confirm deployed builds resolve PowerMux to 1.1.1 or later.
  • Review routing behavior around trailing slash redirects.
  • Check user reports for suspicious redirect complaints.
Prepared
Confidence
high
Sources
3

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-601: User-session and phishing behavior lookup

Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2021-32721 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Medium
CVSS
4.7 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
4.7CVSS 3.1MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N1.62.7Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

4.7Medium
CVSS 3.1 vector shape for CVE-2021-32721Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
AndrewBurianpowermux< 1.1.1Listed
Weakness

CWE details

CWE-601

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-601 · source CWE mapping

URL Redirection to Untrusted Site ('Open Redirect')

URL Redirection to Untrusted Site ('Open Redirect') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs