Remote Code Execution Vulnerability in FreeScout Help Desk Software by FreeScout

CVE-2026-28289

What is CVE-2026-28289?

CVE-2026-28289 represents a critical remote code execution (RCE) vulnerability identified in FreeScout, an open-source help desk software built on PHP's Laravel framework. This software facilitates efficient ticket management and shared inbox functionalities for various organizations. The vulnerability stems from a flaw in the sanitizeUploadedFileName() function, which fails to properly sanitize file names during upload due to a Time-of-Check to Time-of-Use (TOCTOU) issue. Specifically, authenticated users with file upload permissions can exploit this flaw by uploading a malicious .htaccess file prefixed with invisible characters. This allows them to circumvent security checks and execute arbitrary code on the server, compromising the system's integrity and confidentiality.

Potential impact of CVE-2026-28289

1. Remote Code Execution: The primary concern is the ability for attackers to execute arbitrary code on the server. This can lead to unauthorized access to sensitive data, manipulation of application functionality, and potential takeover of the underlying server environment.

2. Data Breaches: Exploitation of this vulnerability could result in significant data breaches. Attackers might access, modify, or exfiltrate sensitive information stored within the FreeScout application, impacting customer privacy and regulatory compliance.

3. Widespread System Compromise: Given that FreeScout is often deployed in environments where tickets and communications may contain sensitive information, the vulnerability could facilitate further attacks within an organization, spreading to other systems and applications connected to the compromised server.

References