CVE-2021-47734

CMSimple 5.4 Authenticated Local File Inclusion Remote Code Execution

High8.6Public exploitEPSS 0.78%

Published: 23 Dec 2025
Updated: 17 Mar 2026
Reserved: 23 Dec 2025
Assigned by: VulnCheck

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.

Public exploit

A reference of the record is tagged as an exploit or proof of concept: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: a proof of concept is public.

ExploitDB-50547 (opens in a new tab)exploit

Timeline

2025
23 Dec 2025
23 Dec 2025
ID reserved
By VulnCheck
23 Dec 2025
23 Dec 2025
Published
2026
17 Mar 20263 months later
17 Mar 2026· 3 months later
Record updated

Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.

Scores

CVSS scores of CVE-2021-47734, by who scored it
Scored by	CVSS	Score	Vector
VulnCheckCNA (assigner)	4.0	High8.6	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
VulnCheckCNA (assigner)	3.1	High7.8	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVDNVD · Modified	4.0	High8.6	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS (exploitation in 30 days): 0.78% · top 44% of all CVEs (7 Nov 2026)
CISA SSVC: Exploitation: poc · Automatable: no · Technical impact: total

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.6.

Weakness

CWE-98: Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion') (opens in a new tab)All about CWE-98 and its CVEs

Affected products

Cmsimple · CMSimple
- affected CMSimple 5.4

References (3)

ExploitDB-50547 (opens in a new tab)exploit
Official CMSimple Homepage (opens in a new tab)product
VulnCheck Advisory: CMSimple 5.4 Authenticated Local File Inclusion Remote Code Execution (opens in a new tab)third-party-advisory

Sources

The same CVE in the primary databases and aggregators, to check against.

Badge for a README or a ticket

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Record last updated 17 Mar 2026, 16:23 UTC.