CVE-2021-47733

MEDIUM

CMSimple 5.4 - Stored Cross-Site Scripting via HTML Unicode Encoding Bypass

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2021-47733. PoCs published by heinjame.

AI-analyzed exploit summary This exploit demonstrates a DOM-based XSS vulnerability in CMSimple <=5.4 by bypassing input filtering via HTML Unicode encoding. The payload is triggered when a victim clicks the delete button after uploading a maliciously named file.

Description

CMSimple 5.4 contains a cross-site scripting vulnerability that allows attackers to bypass input filtering by using HTML to Unicode encoding. Attackers can inject malicious scripts by encoding payloads like ')-alert(1)// and execute arbitrary JavaScript when victims interact with delete buttons.

Exploits (1)

exploitdb WORKING POC
by heinjame · textwebappsphp
https://www.exploit-db.com/exploits/50612

This exploit demonstrates a DOM-based XSS vulnerability in CMSimple <=5.4 by bypassing input filtering via HTML Unicode encoding. The payload is triggered when a victim clicks the delete button after uploading a maliciously named file.

Classification
Working Poc 90%
Attack Type
Xss
Complexity
Trivial
Reliability
Reliable
Target: CMSimple <=5.4
Auth required
Prerequisites: Access to the CMSimple admin panel to upload a file · Victim interaction (clicking the delete button)
MITRE ATT&CK
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (3)

Core 3

Scores

CVSS v3 6.1
EPSS 0.0022
EPSS Percentile 11.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact partial

Details

CWE
CWE-79
Status published
Products (2)
cmsimple/cmsimple 5.4
Cmsimple/CMSimple <=5.4
Published Dec 23, 2025
Tracked Since Feb 18, 2026