CVE-2025-13938 is a stored Cross-site Scripting (XSS) vulnerability classified under CWE-79 that affects the Autotask Technology Integration module within WatchGuard Fireware OS. The vulnerability exists due to improper neutralization of user-supplied input during the generation of web pages served by the Fireware OS management interface. Specifically, versions 12.4 up to 12.11.4, 12.5 up to 12.5.13, and 2025.1 up to 2025.1.2 are impacted. An attacker with high privileges on the device can inject malicious scripts that are stored and later executed in the context of an administrative user's browser session. This can lead to unauthorized actions such as session hijacking, credential theft, or execution of arbitrary commands within the management interface. The vulnerability does not require authentication but does require user interaction, such as an administrator accessing a compromised page. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:H indicates high privileges required, but CVSS vector states PR:H which is high privileges), user interaction required (UI:P), and low scope impact (S:L). No known exploits have been reported in the wild as of the publication date. The vulnerability is rated medium severity with a CVSS score of 4.8. The lack of patches at the time of reporting suggests that organizations should implement compensating controls until updates are available.

For European organizations, this vulnerability poses a moderate risk primarily to network security infrastructure relying on WatchGuard Fireware OS. Successful exploitation could allow attackers to execute malicious scripts within the administrative interface, potentially leading to session hijacking, theft of administrative credentials, or unauthorized configuration changes. This could degrade the confidentiality and integrity of network security controls, potentially allowing further lateral movement or data exfiltration. The impact on availability is limited but could occur if attackers disrupt firewall or VPN configurations. Given the requirement for high privileges and user interaction, the threat is less likely to be exploited remotely without insider access or prior compromise. However, organizations with exposed management interfaces or insufficient access controls are at higher risk. The medium severity rating reflects these factors. European critical infrastructure providers, government agencies, and enterprises using WatchGuard devices for perimeter defense or remote access VPNs should prioritize assessment and mitigation to prevent potential exploitation.

1. Monitor WatchGuard's official channels for patches addressing CVE-2025-13938 and apply them promptly once released. 2. Restrict administrative access to Fireware OS management interfaces to trusted networks and users using network segmentation and VPNs. 3. Enforce strong authentication mechanisms, including multi-factor authentication, to reduce risk from compromised credentials. 4. Implement strict input validation and sanitization on any user inputs that interact with the affected module, if customization is possible. 5. Deploy Content Security Policy (CSP) headers on management interfaces to limit the execution of unauthorized scripts. 6. Regularly audit and monitor logs for suspicious activity related to the Autotask Technology Integration module. 7. Educate administrators to avoid clicking on suspicious links or content that could trigger stored XSS payloads. 8. Consider isolating or disabling the Autotask Technology Integration module if it is not essential to operations until a patch is available. 9. Use web application firewalls (WAFs) capable of detecting and blocking XSS payloads targeting internal management interfaces. 10. Conduct penetration testing and vulnerability assessments focused on the Fireware OS environment to identify and remediate related weaknesses.