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Vulnerabilities

Vulnerability · CVE-2021-47734

CMSimple 5.4 contains an authenticated local file inclusion vulnerability that allows remote attackers to manipulate PHP session files and execute arbitrary code.

Published Dec 23, 2025 · catalog updated Mar 17, 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-2021-47734. EPSS is 0.78%. 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
High8.6
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.78%
Remediation
Vendor / distro source
Affected products
vendor CMSimple CMSimple CMSimple 5.4

CMSimple 5.4 contains an authenticated local file inclusion vulnerability that allows remote attackers to manipulate PHP session files and execute arbitrary code. Attackers can leverage the vulnerability by changing the functions file path and uploading malicious PHP code through session file upload mechanisms.

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 CMSimple 5.4CMSimple 5.4

How to fix CVE-2021-47734

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-2021-47734. EPSS is 0.78%. Act only if a listed version of CMSimple CMSimple is installed.

Which versions are affected?

Compare what you have installed with CMSimple CMSimple CMSimple 5.4 CMSimple 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 0.78%. 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 an authenticated local file inclusion vulnerability that allows remote attackers to manipulate PHP session files and execute arbitrary code. Attackers can leverage the vulnerability by changing the functions file path and uploading malicious PHP code through session file upload mechanisms.

  2. Mar 17, 2026 · EUVD

    Updated

    CMSimple 5.4 contains an authenticated local file inclusion vulnerability that allows remote attackers to manipulate PHP session files and execute arbitrary code. Attackers can leverage the vulnerability by changing the functions file path and uploading malicious PHP code through session file upload mechanisms.

Sources

  • CVE.orgVulnerability recordCVE-2021-47734

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-47734

    30-day exploitation probability 0.78%

    first.org
  • EUVDVulnerability recordEUVD-2025-204835

    CMSimple 5.4 contains an authenticated local file inclusion vulnerability that allows remote attackers to manipulate PHP session files and execute arbitrary code. Attackers can leverage the vulnerability by changing the functions file path and uploading malicious PHP code through

    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