CVE-2025-9242 is an out-of-bounds write vulnerability classified under CWE-787 found in WatchGuard Fireware OS, specifically impacting the VPN components using IKEv2 with dynamic gateway peer configurations. This vulnerability exists in Fireware OS versions from 11.10.2 up to 11.12.4_Update1, 12.0 up to 12.11.3, and 2025.0. The flaw allows a remote attacker to write outside the bounds of allocated memory, which can lead to arbitrary code execution on the affected device. Notably, exploitation requires no authentication or user interaction, increasing the risk of automated or wormable attacks. The vulnerability affects both Mobile User VPN and Branch Office VPN functionalities, which are critical for secure remote access and site-to-site connectivity. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N) reflects network attack vector, low complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. While no public exploits are currently known, the critical nature of the vulnerability and the widespread use of WatchGuard Fireware OS in enterprise and government environments make it a high-priority security issue. The absence of patch links suggests that fixes may be forthcoming or in development, emphasizing the need for proactive mitigation.

The vulnerability enables remote unauthenticated attackers to execute arbitrary code on Fireware OS devices, potentially leading to full compromise of the firewall or VPN gateway. This can result in unauthorized access to internal networks, interception or manipulation of sensitive data, disruption of VPN services, and lateral movement within affected organizations. Given the critical role of Fireware OS in securing remote access and branch office connectivity, exploitation could severely impact confidentiality, integrity, and availability of enterprise networks. Organizations relying on WatchGuard VPN solutions for secure communications may face data breaches, operational downtime, and reputational damage. The ease of exploitation and lack of authentication requirements increase the likelihood of attacks, especially in environments exposed to the internet. The vulnerability could also be leveraged as a foothold for advanced persistent threats targeting critical infrastructure or government networks.

Organizations should immediately inventory their WatchGuard Fireware OS deployments to identify affected versions and configurations using Mobile User VPN or Branch Office VPN with IKEv2 and dynamic gateway peers. Until patches are released, network-level mitigations include restricting VPN access to trusted IP ranges, implementing strict firewall rules to limit exposure of VPN endpoints, and monitoring network traffic for anomalous activity targeting VPN services. Deploying intrusion detection/prevention systems with updated signatures can help detect exploitation attempts. Administrators should disable or reconfigure dynamic gateway peer settings if feasible to reduce attack surface. Regularly reviewing VPN logs and enabling detailed auditing can aid in early detection of exploitation. Once patches become available, organizations must prioritize timely updates and validate patch deployment across all affected devices. Additionally, segmenting VPN gateways from critical internal resources can limit potential damage from successful exploitation.