CVE-2019-18873

CRITICAL

FUDForum 3.0.9 - Stored Cross-Site Scripting and Remote Code Execution via User-Agent Header

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 3 public exploits for CVE-2019-18873. PoCs published by liquidsky, fuzzlove, fuzzlove-group.

AI-analyzed exploit summary This exploit leverages stored XSS vulnerabilities in FUDForum 3.0.9 to achieve remote code execution by uploading a PHP shell. The attack involves injecting malicious JavaScript via username or user-agent fields, which executes when an admin views user information.

Description

FUDForum 3.0.9 is vulnerable to Stored XSS via the User-Agent HTTP header. This may result in remote code execution. An attacker can use a user account to fully compromise the system via a GET request. When the admin visits user information under "User Manager" in the control panel, the payload will execute. This will allow for PHP files to be written to the web root, and for code to execute on the remote server. The problem is in admsession.php and admuser.php.

Exploits (3)

exploitdb WORKING POC
by liquidsky · textwebappsphp
https://www.exploit-db.com/exploits/47650

This exploit leverages stored XSS vulnerabilities in FUDForum 3.0.9 to achieve remote code execution by uploading a PHP shell. The attack involves injecting malicious JavaScript via username or user-agent fields, which executes when an admin views user information.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: FUDForum 3.0.9
Auth required
Prerequisites: Registered user account · Admin interaction to trigger XSS
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 7 stars
by fuzzlove · poc
https://github.com/fuzzlove/FUDforum-XSS-RCE

This repository contains a functional exploit for CVE-2019-18873 and CVE-2019-18839, targeting FUDForum 3.0.9. The exploit leverages stored XSS vulnerabilities in the username and User-Agent fields to achieve remote code execution by uploading a PHP shell.

Classification
Working Poc 95%
Attack Type
Xss
Complexity
Moderate
Reliability
Reliable
Target: FUDForum 3.0.9
Auth required
Prerequisites: Registered user account · Admin interaction with user information
devstral-2 · analyzed Feb 19, 2026 Full analysis →
gitlab WORKING POC
by fuzzlove-group · poc
https://gitlab.com/fuzzlove-group/FUDforum-XSS-RCE

This repository contains a functional exploit for CVE-2019-18873 and CVE-2019-18839, demonstrating stored XSS vulnerabilities in FUDForum 3.0.9 that can lead to remote code execution. The exploit includes detailed steps and a JavaScript payload (fud.js) that, when triggered by an admin, uploads a PHP shell to the target system.

Classification
Working Poc 95%
Attack Type
Xss
Complexity
Moderate
Reliability
Reliable
Target: FUDForum 3.0.9
Auth required
Prerequisites: Registered user account · Admin interaction to trigger payload
devstral-2 · analyzed Feb 23, 2026 Full analysis →

References (2)

Core 2
Core References
Exploit, Third Party Advisory x_refsource_misc
https://github.com/fuzzlove/FUDforum-XSS-RCE
Third Party Advisory x_refsource_misc
https://sourceforge.net/p/fudforum/code/6321/

Scores

CVSS v3 9.0
EPSS 0.0815
EPSS Percentile 94.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

Details

CWE
CWE-78 CWE-79
Status published
Products (1)
fudforum/fudforum 3.0.9
Published Nov 12, 2019
Tracked Since Feb 18, 2026