How severe is CVE-2021-47734?

CVE-2021-47734 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-47734 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-47734?

CVE-2021-47734 affects Cmsimple. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-47734?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2021-47734 have an EU (EUVD) identifier?

Yes. CVE-2021-47734 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-204835.

When was CVE-2021-47734 published?

CVE-2021-47734 was published on 2025-12-23 and last updated on 2026-06-17.

CVE-2021-47734

CVE-2021-47734 is a high-severity vulnerability in Cmsimple with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-98.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v4: 8.6
EPSS exploit prediction: 1% (49th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-204835
Weakness: CWE-98
Affected product: Cmsimple
Published: 2025-12-23
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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. Attackers can leverage the vulnerability by changing the functions file path and uploading malicious PHP code through session file upload mechanisms.
How severe is CVE-2021-47734?: CVE-2021-47734 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-47734 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-47734?: CVE-2021-47734 affects Cmsimple. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-47734?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2021-47734 have an EU (EUVD) identifier?: Yes. CVE-2021-47734 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-204835.
When was CVE-2021-47734 published?: CVE-2021-47734 was published on 2025-12-23 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:cmsimple:cmsimple:5.4:*:*:*:*:*:*:*

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