Cybersecurity Vulnerabilities

CVE-2025-13937: Stored XSS Threatens WatchGuard Fireware OS

Overview

CVE-2025-13937 details a stored Cross-Site Scripting (XSS) vulnerability discovered in the ConnectWise Technology Integration module of WatchGuard Fireware OS. This vulnerability allows an attacker to inject malicious scripts into the system, which are then stored and executed whenever a user interacts with the affected area of the Fireware OS interface. This vulnerability affects Fireware OS versions 12.4 up to and including 12.11.4, 12.5 up to and including 12.5.13, and 2025.1 up to and including 2025.1.2.

Technical Details

The vulnerability arises from the improper neutralization of user-supplied input during the generation of web pages within the ConnectWise Technology Integration module. Specifically, the system fails to adequately sanitize input, allowing an attacker to inject arbitrary JavaScript code. Because the XSS is stored, the malicious script is persistently injected into the application and executed in the browsers of unsuspecting users who access the compromised section of the Fireware OS interface. The exact injection point and the specific input parameter are detailed in WatchGuard’s advisory.

CVSS Analysis

Currently, the CVSS score and severity level for CVE-2025-13937 are listed as N/A. However, it is crucial to understand that stored XSS vulnerabilities can pose a significant risk. Even without an official CVSS score, the potential impact of successful exploitation warrants immediate attention and mitigation.

Possible Impact

A successful exploitation of this stored XSS vulnerability could have several severe consequences:

  • Account Compromise: An attacker could steal user session cookies or credentials, gaining unauthorized access to the Fireware OS.
  • Malware Distribution: The injected script could redirect users to malicious websites, leading to malware infections.
  • Defacement: The attacker could modify the appearance or functionality of the Fireware OS interface, disrupting normal operations.
  • Data Theft: Sensitive data displayed within the Fireware OS interface could be accessed and exfiltrated by the attacker.
  • Privilege Escalation: Depending on the privileges of the compromised user, the attacker might be able to escalate privileges and gain administrative control over the system.

Mitigation or Patch Steps

To mitigate the risk posed by CVE-2025-13937, it is highly recommended to take the following actions:

  1. Upgrade Fireware OS: Immediately upgrade to a version of Fireware OS that addresses this vulnerability. Refer to WatchGuard’s security advisory (linked below) for specific version details and upgrade instructions.
  2. Review ConnectWise Integration: If not in use, consider disabling the ConnectWise Technology Integration module until the upgrade is complete.
  3. Web Application Firewall (WAF): Implement or configure a Web Application Firewall (WAF) to detect and block malicious XSS payloads.
  4. Input Validation: Ensure all user-supplied input is properly validated and sanitized to prevent the injection of malicious scripts (this is a preventative measure for developers).

References

WatchGuard Security Advisory WGSA-2025-00022

Cybersecurity specialist and founder of Gowri Shankar Infosec - a professional blog dedicated to sharing actionable insights on cybersecurity, data protection, server administration, and compliance frameworks including SOC 2, PCI DSS, and GDPR.

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