A critical security vulnerability, tracked as CVE-2025-9242, was discovered in WatchGuard Fireware OS, which powers WatchGuard’s Firebox network security appliances. This flaw is an out-of-bounds write vulnerability in the iked process, specifically within the function 'ike2_ProcessPayload_CERT' in the file 'src/ike/iked/v2/ike2_payload_cert.c'. The vulnerability arises due to a missing length check on the identification buffer, allowing a remote, unauthenticated attacker to trigger a stack-based buffer overflow. Exploitation of this flaw enables arbitrary code execution during the IKE_SA_AUTH phase of the IKEv2 handshake, which is used to establish VPN tunnels. The vulnerability affects both mobile user VPNs and branch office VPNs configured with dynamic gateway peers, making it a significant risk for organizations relying on these features. Fireware OS versions 11.10.2 up to and including 11.12.4_Update1, 12.0 up to and including 12.11.3, and 2025.1 are impacted, with fixes released in 2025.1.1, 12.11.4, 12.3.1_Update3 (FIPS-certified), and 12.5.13 for specific models. The 11.x branch has reached end-of-life and is no longer supported. Security researchers, including McCaulay Hudson of watchTowr Labs, highlighted that the vulnerability is particularly attractive to ransomware groups due to its remote, unauthenticated nature and the fact that it targets internet-exposed perimeter appliances. WatchGuard’s Fireware OS is widely deployed, protecting over 250,000 small and midsize enterprises and more than 10 million endpoints globally, amplifying the potential impact of this vulnerability. The flaw was disclosed and patched following responsible disclosure, with WatchGuard issuing an advisory and urging customers to update affected devices immediately. The vulnerability underscores the ongoing risk posed by classic buffer overflow issues, even in modern enterprise-grade security appliances. Researchers were able to reproduce the exploit, demonstrating the ease with which attackers could compromise vulnerable systems. The lack of mainstream exploit mitigations in the affected code path further increases the risk of successful exploitation. Organizations using WatchGuard Fireware OS are advised to review their VPN configurations, apply the latest patches, and consider additional monitoring for signs of exploitation. The incident highlights the importance of timely patch management and the persistent threat posed by memory safety vulnerabilities in critical infrastructure.

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Public reporting described how the flaw in the iked process, specifically ike2_ProcessPayload_CERT during the IKE_SA_AUTH phase, could be exploited to obtain a Python shell and then escalate to a full Linux shell on vulnerable devices.
By the time of public reporting, WatchGuard had issued fixes for supported Fireware OS versions affected by CVE-2025-9242, while end-of-life versions remained unpatched.
watchTowr Labs publicly disclosed CVE-2025-9242, a critical out-of-bounds write in WatchGuard Fireware OS's IKEv2 handling that can allow unauthenticated remote code execution on affected devices.
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