CVE-2025-6947 is a medium-severity vulnerability classified under CWE-79, indicating an Improper Neutralization of Input During Web Page Generation, commonly known as Cross-site Scripting (XSS). This vulnerability affects WatchGuard Fireware OS versions from 12.0 through 12.11.2. Specifically, it allows a stored XSS attack via the SIP Proxy module. The vulnerability requires an authenticated administrator session on a locally managed Firebox device, meaning an attacker must already have high-level access to the device's management interface. The flaw arises because the Fireware OS does not properly sanitize or neutralize input data when generating web pages, allowing malicious scripts to be stored and subsequently executed in the context of the administrator's browser session. The CVSS 4.0 base score is 4.8, reflecting a medium severity level. The attack vector is network-based (AV:N), with low attack complexity (AC:L), no privileges required (PR:H indicates high privileges are required, so this is a discrepancy in the vector but the description clarifies that admin privileges are necessary), and user interaction is required (UI:P). The vulnerability does not impact confidentiality, integrity, or availability directly but can be leveraged to execute arbitrary scripts in the administrator's browser, potentially leading to session hijacking, credential theft, or further administrative control compromise. No known exploits are currently in the wild, and no patches have been linked yet, indicating that remediation may still be pending or in development. The vulnerability is scoped to the local management interface and requires authenticated access, limiting its exposure primarily to insiders or attackers who have already compromised administrative credentials or access paths.

For European organizations, this vulnerability poses a moderate risk primarily to network security infrastructure managed via WatchGuard Fireware OS devices. Since Firebox appliances are commonly deployed in enterprise environments for firewall, VPN, and network security management, exploitation could allow an attacker with administrative access to execute malicious scripts within the management console. This could lead to session hijacking or unauthorized command execution, potentially compromising the firewall's configuration and network security posture. The impact is particularly significant for organizations relying on Firebox devices for perimeter defense, as a compromised firewall can undermine the entire network's security. Additionally, the requirement for authenticated admin access means that insider threats or attackers who have gained administrative credentials through phishing or credential theft could leverage this vulnerability to escalate their control. European organizations with strict compliance requirements (e.g., GDPR) must consider the risk of unauthorized access and data exposure resulting from such an attack. While the vulnerability does not directly affect confidentiality or availability, the indirect consequences of firewall compromise could be severe, including data breaches or network outages.

To mitigate this vulnerability, European organizations should: 1) Immediately restrict administrative access to Firebox devices to trusted personnel and secure management interfaces using strong authentication methods such as multi-factor authentication (MFA). 2) Limit network exposure of the management interface by enforcing access controls, such as IP whitelisting and VPN-only access for administrative sessions. 3) Monitor administrative sessions and logs for unusual activity that could indicate exploitation attempts. 4) Apply any available patches or updates from WatchGuard as soon as they are released; if no patch is currently available, engage with WatchGuard support for recommended interim mitigations. 5) Conduct regular security training for administrators to recognize phishing and credential theft attempts that could lead to unauthorized access. 6) Employ web application firewalls (WAFs) or intrusion detection systems (IDS) to detect and block suspicious input patterns targeting the SIP Proxy module. 7) Consider network segmentation to isolate management interfaces from general user networks to reduce the attack surface. These steps go beyond generic advice by focusing on access control hardening, monitoring, and proactive engagement with vendor support.