CVE-2020-23839

MEDIUM

GetSimple CMS 3.3.16 - Reflected Cross-Site Scripting in Login Portal

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 2 public exploits for CVE-2020-23839. PoCs published by boku, boku7.

AI-analyzed exploit summary This exploit leverages a reflected XSS vulnerability in GetSimple CMS 3.3.16 to steal admin credentials, chain XHR requests, and achieve RCE via a PHP webshell injection. The attack requires admin interaction to trigger the payload.

Description

A Reflected Cross-Site Scripting (XSS) vulnerability in GetSimple CMS v3.3.16, in the admin/index.php login portal webpage, allows remote attackers to execute JavaScript code in the client's browser and harvest login credentials after a client clicks a link, enters credentials, and submits the login form.

Exploits (2)

exploitdb WORKING POC
by boku · pythonwebappsphp
https://www.exploit-db.com/exploits/49726

This exploit leverages a reflected XSS vulnerability in GetSimple CMS 3.3.16 to steal admin credentials, chain XHR requests, and achieve RCE via a PHP webshell injection. The attack requires admin interaction to trigger the payload.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Complex
Reliability
Reliable
Target: GetSimple CMS v3.3.16
Auth required
Prerequisites: Admin must visit crafted URL and log in
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 11 stars
by boku7 · poc
https://github.com/boku7/CVE-2020-23839

This repository contains two Python scripts exploiting CVE-2020-23839, a reflected XSS vulnerability in GetSimple CMS v3.3.16. The scripts chain the XSS to achieve RCE by injecting a PHP webshell into the CMS theme files.

Classification
Working Poc 95%
Attack Type
Xss
Complexity
Moderate
Reliability
Reliable
Target: GetSimple CMS v3.3.16
No auth needed
Prerequisites: Target must be running GetSimple CMS v3.3.16 · Admin must visit the crafted URL and log in
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (4)

Core 4
Core References
Exploit, Third Party Advisory x_refsource_misc
https://github.com/GetSimpleCMS/GetSimpleCMS/issues/1330
Third Party Advisory, VDB Entry exploit x_refsource_exploit-db
https://www.exploit-db.com/exploits/49726
Third Party Advisory x_refsource_misc
https://github.com/boku7/CVE-2020-23839

Scores

CVSS v3 6.1
EPSS 0.1046
EPSS Percentile 95.2%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Details

CWE
CWE-79
Status published
Products (1)
get-simple/getsimple_cms 3.3.16
Published Sep 01, 2020
Tracked Since Feb 18, 2026