CVE-2026-28289

CRITICAL

FreeScout <=1.8.206 - Authenticated RCE

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 5 public exploits for CVE-2026-28289. PoCs published by XiaomingX, exploitintel, 0xBlackash, including Metasploit module exploits/multi/http/freescout_htaccess_rce.

AI-analyzed exploit summary The repository contains a functional Python script that exploits CVE-2026-28289, a zero-click RCE vulnerability in FreeScout. The exploit sends a crafted email with malicious attachments (a Unicode-prefixed .htaccess and a PHP webshell) to bypass filename sanitization and achieve remote code execution.

Description

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. A patch bypass vulnerability for CVE-2026-27636 in FreeScout 1.8.206 and earlier allows any authenticated user with file upload permissions to achieve Remote Code Execution (RCE) on the server by uploading a malicious .htaccess file using a zero-width space character prefix to bypass the security check. The vulnerability exists in the sanitizeUploadedFileName() function in app/Http/Helper.php. The function contains a Time-of-Check to Time-of-Use (TOCTOU) flaw where the dot-prefix check occurs before sanitization removes invisible characters. This vulnerability is fixed in 1.8.207.

Exploits (5)

github WORKING POC 10 stars
by XiaomingX · pythonpoc
https://github.com/XiaomingX/data-cve-poc-py-v1/tree/main/2026/CVE-2026-28289

The repository contains a functional Python script that exploits CVE-2026-28289, a zero-click RCE vulnerability in FreeScout. The exploit sends a crafted email with malicious attachments (a Unicode-prefixed .htaccess and a PHP webshell) to bypass filename sanitization and achieve remote code execution.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: FreeScout ≤ 1.8.206
No auth needed
Prerequisites: SMTP server access · valid email credentials · target FreeScout mailbox
devstral-2 · analyzed Mar 06, 2026 Full analysis →
github WORKING POC 2 stars
by exploitintel · cpoc
https://github.com/exploitintel/eip-pocs-and-cves/tree/main/CVE-2026-28289

This repository contains functional exploit code for CVE-2026-28289, a TOCTOU vulnerability in FreeScout ≤1.8.206 that allows authenticated RCE via .htaccess upload bypass using Unicode manipulation. The PoC includes multiple attack vectors and a Docker-based lab environment for testing.

Classification
Working Poc 100%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: FreeScout ≤1.8.206
Auth required
Prerequisites: Docker and Docker Compose for lab setup · Python 3 with requests library · Valid FreeScout credentials for authenticated attack
devstral-2 · analyzed Mar 14, 2026 Full analysis →
nomisec WORKING POC 1 stars
by 0xBlackash · poc
https://github.com/0xBlackash/CVE-2026-28289

The repository contains a functional Python script that exploits CVE-2026-28289, a zero-click RCE vulnerability in FreeScout. The exploit sends a malicious email with a Unicode-prefixed .htaccess file and a PHP webshell, bypassing filename sanitization to achieve remote code execution.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: FreeScout ≤ 1.8.206
No auth needed
Prerequisites: SMTP server access · valid email credentials · target FreeScout mailbox
devstral-2 · analyzed Apr 09, 2026 Full analysis →
nomisec WORKING POC
by 0xAshwesker · poc
https://github.com/0xAshwesker/CVE-2026-28289

The repository contains a functional Python script that exploits CVE-2026-28289, a zero-click RCE vulnerability in FreeScout. The exploit sends a malicious email with a Unicode-prefixed .htaccess file and a PHP webshell, bypassing filename sanitization to achieve remote code execution.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: FreeScout <= 1.8.206
No auth needed
Prerequisites: SMTP server access · valid email credentials · target FreeScout instance
devstral-2 · analyzed Mar 06, 2026 Full analysis →
metasploit WORKING POC EXCELLENT
by offensiveee, Nir Zadok (nirzadokox) <OX Security>, Moses Bhardwaj (MosesOX) <OX Security> · rubypocphp
https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/multi/http/freescout_htaccess_rce.rb

This Metasploit module exploits CVE-2026-28289 in FreeScout <= 1.8.206 by sending a crafted email with a ZWSP-prefixed .htaccess attachment, which bypasses filename sanitization and achieves RCE via PHP code execution.

Classification
Working Poc 100%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: FreeScout <= 1.8.206
No auth needed
Prerequisites: Valid mailbox email address · Web-accessible attachment storage
devstral-2 · analyzed Apr 09, 2026 Full analysis →

Scores

CVSS v3 10.0
EPSS 0.1622
EPSS Percentile 95.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact total

Details

CWE
CWE-434
Status published
Products (1)
freescout/freescout < 1.8.207
Published Mar 03, 2026
Tracked Since Mar 04, 2026