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Vulnerabilities

Vulnerability · CVE-2021-47733

CMSimple 5.4 contains a cross-site scripting vulnerability that allows attackers to bypass input filtering by using HTML to Unicode encoding.

Published Dec 23, 2025 · catalog updated Apr 7, 2026 · CMSimple CMSimple

Last checked Nov 2, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2021-47733. EPSS is 0.26%. Act only if a listed version of CMSimple CMSimple is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium5.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.26%
Remediation
Vendor / distro source
Affected products
vendor CMSimple CMSimple ≤5.4

CMSimple 5.4 contains a cross-site scripting vulnerability that allows attackers to bypass input filtering by using HTML to Unicode encoding. Attackers can inject malicious scripts by encoding payloads like ')-alert(1)// and execute arbitrary JavaScript when victims interact with delete buttons.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor CMSimple CMSimple ≤5.4≤5.4

How to fix CVE-2021-47733

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2021-47733. EPSS is 0.26%. Act only if a listed version of CMSimple CMSimple is installed.

Which versions are affected?

Compare what you have installed with CMSimple CMSimple ≤5.4 ≤5.4. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.26%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Dec 23, 2025 · EUVD

    Detected

    CMSimple 5.4 contains a cross-site scripting vulnerability that allows attackers to bypass input filtering by using HTML to Unicode encoding. Attackers can inject malicious scripts by encoding payloads like ')-alert(1)// and execute arbitrary JavaScript when victims interact with delete buttons.

  2. Apr 7, 2026 · EUVD

    Updated

    CMSimple 5.4 contains a cross-site scripting vulnerability that allows attackers to bypass input filtering by using HTML to Unicode encoding. Attackers can inject malicious scripts by encoding payloads like ')-alert(1)// and execute arbitrary JavaScript when victims interact with delete buttons.

Sources

  • CVE.orgVulnerability recordCVE-2021-47733

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-47733

    30-day exploitation probability 0.26%

    first.org
  • EUVDVulnerability recordEUVD-2025-204822

    CMSimple 5.4 contains a cross-site scripting vulnerability that allows attackers to bypass input filtering by using HTML to Unicode encoding. Attackers can inject malicious scripts by encoding payloads like ')-alert(1)// and execute arbitrary JavaScript when victims interact with

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Nov 2, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 2, 2026
  • CVE.orgOct 30, 2026
  • EUVDOct 30, 2026