CVE-2025-4805 is a Stored Cross-Site Scripting (XSS) vulnerability identified in WatchGuard Fireware OS versions 12.0 through 12.11.1. This vulnerability arises from improper neutralization of input during web page generation, classified under CWE-79. Specifically, the flaw allows malicious scripts to be stored and executed within the administrative web interface of the Firebox device. Exploitation requires an authenticated administrator session on a locally managed Firebox, meaning an attacker must already have high-level access to the device's management interface. The vulnerability does not require network-level authentication but does require privileged credentials and some user interaction (e.g., an administrator viewing a compromised page). The CVSS 4.0 base score is 4.8 (medium severity), reflecting the limited attack vector (local network), the need for high privileges, and user interaction. The vulnerability does not impact confidentiality, integrity, or availability directly but could enable further attacks such as session hijacking or privilege escalation if exploited. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability affects Fireware OS, which is the operating system for WatchGuard Firebox network security appliances widely used for firewall, VPN, and network security management.

For European organizations, this vulnerability poses a moderate risk primarily to network security administrators managing WatchGuard Firebox devices locally. If exploited, an attacker with administrative credentials could inject malicious scripts into the management interface, potentially leading to session hijacking, credential theft, or manipulation of device settings. This could undermine the security posture of the network perimeter, allowing attackers to bypass firewall rules or disrupt VPN configurations. Given that Firebox devices are often deployed in critical infrastructure, government agencies, and enterprises across Europe, successful exploitation could lead to lateral movement within networks or data exfiltration. However, the requirement for authenticated access limits the risk to insider threats or attackers who have already compromised administrative credentials. The absence of known exploits in the wild reduces immediate urgency but does not eliminate the risk, especially in environments where credential hygiene is weak or where administrators access devices from insecure networks.

Organizations should prioritize the following mitigations: 1) Restrict administrative access to Firebox devices strictly to trusted networks and use multi-factor authentication (MFA) for all administrator accounts to reduce the risk of credential compromise. 2) Monitor and audit administrative sessions for unusual activity that could indicate exploitation attempts. 3) Apply the latest Fireware OS updates as soon as patches become available from WatchGuard to remediate the vulnerability. 4) Implement network segmentation to isolate management interfaces from general user networks, minimizing exposure. 5) Educate administrators on the risks of XSS and the importance of not clicking on suspicious links or executing untrusted scripts within the management interface. 6) Use Web Application Firewalls (WAFs) or intrusion detection systems (IDS) to detect anomalous web traffic patterns targeting the Firebox management interface. These steps go beyond generic advice by focusing on access control, monitoring, and network architecture specific to Firebox deployments.