CVE-2021-38321Network attack vector

Script execution via unescaped selected_menu reflection

Published Sep 9, 2021 · Updated May 5, 2025

Reflected XSS in Sean Sullivan Custom Menu Plugin 1.3.3 and earlier allows remote attackers to execute scripts via selected_menu. custom-menus.php reflects the selected_menu request parameter into an HTML response without neutralizing script markup. Exploitation requires a user to open a crafted request, allowing script execution in that user's browser context.

CVSS severity6.1
Medium
EPSS probability0.90%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in Sean Sullivan Custom Menu Plugin 1.3.3 and earlier allows remote attackers to execute scripts via selected_menu. custom-menus.php reflects the selected_menu request parameter into an HTML response without neutralizing script markup. Exploitation requires a user to open a crafted request, allowing script execution in that user's browser context.

The record

CVE
CVE-2021-38321
Published
Sep 9, 2021
Updated
May 5, 2025
Vendor
Sean Sullivan
Product
Custom Menu Plugin
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 9, 2021CVE publishedPublication date reported by the CVE source.
  2. May 5, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.3.3 <=1.3.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Sean Sullivan · Custom Menu Pluginversion=1.3.3 <=1.3.3

Published CVSS scores

4.3NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.1WordfenceCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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