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Vulnerability record · CVE-2021-47735 · published 23 December 2025

CVE-2021-47735: Cmsimple code injection vulnerability

Cmsimple · Cmsimple

CMSimple 5.4 contains an authenticated remote code execution vulnerability that allows logged-in attackers to inject malicious PHP code into template files. Attackers can exploit the template editing functionality by crafting a reverse shell payload and saving it through the template editing endpoint with a valid CSRF token.

8.6 CVSS 4.0 High EPSS 0.88% · top 42.4% CWE-94 · Code injection
8.6CVSS 4.0 base score
0.88%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References, 1 tagged exploit
17 Jun 2026Last modified by NVD

Description

CMSimple 5.4 contains an authenticated remote code execution vulnerability that allows logged-in attackers to inject malicious PHP code into template files. Attackers can exploit the template editing functionality by crafting a reverse shell payload and saving it through the template editing endpoint with a valid CSRF token.

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:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://www.cmsimple.org/ Product
https://www.exploit-db.com/exploits/50356 Exploit
https://www.vulncheck.com/advisories/cmsimple-authenticated-remote-code-execution-via-template-editing Third Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2021-43741Cmsimple path traversal vulnerabilityCMSimple 5.4 is vulnerable to Directory Traversal. The vulnerability exists when a user changes the file name to malicious file on config.php leading…EPSS 4.7%9.1CVE-2024-57548Cmsimple incorrect default permissions vulnerabilityCMSimple 5.16 allows the user to edit log.php file via print page.EPSS 0.47%8.6CVE-2021-47734Cmsimple php remote file inclusion vulnerabilityCMSimple 5.4 contains an authenticated local file inclusion vulnerability that allows remote attackers to manipulate PHP session files and execute ar…EPSS 0.78%8.6CVE-2024-58280Cmsimple vulnerabilityCMSimple 5.15 contains a remote command execution vulnerability that allows authenticated attackers to modify file extensions and upload malicious PH…EPSS 0.94%7.5CVE-2024-57547Cmsimple incorrect permission assignment vulnerabilityInsecure Permissions vulnerability in CMSimple v.5.16 allows a remote attacker to obtain sensitive information via a crafted script to the Functional…EPSS 0.57%7.5CVE-2024-57549Cmsimple path traversal vulnerabilityCMSimple 5.16 allows the user to read cms source code through manipulation of the file name in the file parameter of a GET request.EPSS 0.66%7.5CVE-2024-57546Cmsimple vulnerabilityAn issue in CMSimple v.5.16 allows a remote attacker to obtain sensitive information via a crafted script to the validate link function.EPSS 0.58%7.4CVE-2024-33423Cmsimple vulnerabilityCross-Site Scripting (XSS) vulnerability in the Settings menu of CMSimple v5.15 allows attackers to execute arbitrary web scripts or HTML via a craft…EPSS 0.56%

Source: NIST National Vulnerability Database (record CVE-2021-47735), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.