CVE-2021-47734CWE-98

CMSimple 5.4 Authenticated Local File Inclusion Remote Code Execution

High · published December 23, 2025

CVSS v4.0
8.6
EPSS
1%
Percentile
55.5
In the wild
Unconfirmed
What it is

⚡ An authenticated local file inclusion vulnerability lurks in CMSimple 5.4, ready to tiptoe into your PHP session files! Think of it like a sneaky waiter who swaps out your meal order while you’re distracted — an attacker can change the file path and slip in some malicious code while you’re not looking! If exploited, this vulnerability allows attackers to execute arbitrary code, potentially leading to full control over the server and devastating consequences. They could manipulate sensitive data, wreak havoc on your site, or even steal user information!

Put simply

Think of it like a sneaky waiter who swaps out your meal order while you’re distracted — an attacker can change the file path and slip in some malicious code while you’re not looking! This vulnerability stems from a flaw in how CMSimple handles PHP session files, allowing authenticated users to manipulate file paths and upload malicious PHP code, thus executing it on the server.

What to do

If exploited, this vulnerability allows attackers to execute arbitrary code, potentially leading to full control over the server and devastating consequences. They could manipulate sensitive data, wreak havoc on your site, or even steal user information! Immediately update to the latest version of CMSimple to eliminate this vulnerability. Additionally, review your file upload mechanisms and ensure proper validation to prevent path manipulation. Don't forget to restrict access to sensitive directories! You've got this! Follow these steps and you'll be back on track in no time! 🛡️

The record
Technical detail
CVSS v4.0
8.6 · HIGH
Vector
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
EPSS
0.00782 · 55.5th percentile
Weakness
CWE-98 · Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion')
Published
2025-12-23T19:34Z
EPSS history
Timeline
  • 23 DEC 19:34Z
    CMSimple 5.4 Authenticated Local File Inclusion Remote Code Execution
    cvelistv5