CVE-2021-47732Public exploitNetwork attack vector

Browser script execution via unfiltered External input

Published Dec 23, 2025 · Updated Apr 7, 2026

Stored XSS in CMSimple 5.2 allows attackers to execute JavaScript in a user's browser through the Filebrowser External field. The Filebrowser External setting accepts special characters without filtering and persistently renders the supplied script when the Page or Files tab is opened. The attacker must be able to write the CMS setting, and a user must open either tab; execution is confined to that user's browser context.

CVSS severity5.1
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in CMSimple 5.2 allows attackers to execute JavaScript in a user's browser through the Filebrowser External field. The Filebrowser External setting accepts special characters without filtering and persistently renders the supplied script when the Page or Files tab is opened. The attacker must be able to write the CMS setting, and a user must open either tab; execution is confined to that user's browser context.

The record

CVE
CVE-2021-47732
Published
Dec 23, 2025
Updated
Apr 7, 2026
Vendor
CMSimple
Product
CMSimple
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Dec 23, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 7, 2026Record 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=CMSimple 5.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

CMSimple · CMSimpleversion=CMSimple 5.2

Published CVSS scores

6.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.1VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
5.1VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA: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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript

Public exploit references

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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