Critical Remote Code Execution Vulnerability in WatchGuard Fireware OS VPN
A critical vulnerability, tracked as CVE-2025-9242, has been discovered in WatchGuard's Fireware OS, affecting a wide range of Firebox network security appliances. This flaw is an out-of-bounds write in the 'iked' process, which is responsible for handling IKEv2 VPN negotiations. The vulnerability allows remote attackers to execute arbitrary code on affected devices without authentication, posing a severe risk to organizations relying on these appliances for network security. The issue specifically impacts devices configured with mobile user VPNs or branch office VPNs using IKEv2 with dynamic gateway peers. Security researchers have demonstrated that attackers can exploit this bug by sending specially crafted IKEv2 packets during the IKE_SA_AUTH phase, triggering a buffer overflow in the ike2_ProcessPayload_CERT function. Once exploited, attackers can gain control of the instruction pointer, establish Python interactive shells over TCP, and escalate to a full Linux shell by remounting filesystems and deploying BusyBox binaries. The vulnerability has been assigned a CVSS score of 9.3, underscoring its critical nature. According to scans by The Shadowserver Foundation, nearly 76,000 Firebox appliances remain exposed and vulnerable on the public internet, with the highest concentrations in the United States, Germany, Italy, the United Kingdom, Canada, and France. Affected Fireware OS versions include 11.10.2 through 11.12.4_Update1, the entire 12.0 series up to 12.11.3, and the 2025.1 release, impacting both older and newer Firebox models. WatchGuard has released patches in versions 12.3.1_Update3, 12.5.13, 12.11.4, and 2025.1.1 to address the vulnerability. Devices running version 11.x are no longer supported and will not receive security updates, prompting the vendor to recommend upgrading to a supported version. For appliances configured only with Branch Office VPNs to static gateway peers, WatchGuard has provided documentation for securing connections as a temporary workaround. The vulnerability transforms trusted security appliances into potential entry points for attackers, threatening the integrity of network defenses. Organizations are urged to assess their Firebox deployments, prioritize patching, and review VPN configurations to mitigate the risk. The widespread exposure of vulnerable devices highlights the urgency of remediation efforts. WatchGuard's disclosure and the subsequent public scanning have brought significant attention to the issue, emphasizing the importance of timely patch management in network security infrastructure. Failure to address this vulnerability could result in unauthorized access, lateral movement, and compromise of sensitive internal networks. The incident serves as a stark reminder of the risks posed by critical flaws in security appliances and the need for continuous monitoring and rapid response.

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How this story unfolded
3 events from the most recent confirmed update back to the earliest known activity.
More than 75,000 vulnerable Firebox appliances remain exposed a month later
On October 21, 2025, reporting indicated that over 75,000 internet-exposed WatchGuard Firebox devices were still vulnerable more than a month after patches became available. The affected systems were especially concentrated in the U.S., Germany, Italy, the U.K., Canada, and France, underscoring slow patch adoption.
Shadowserver finds nearly 76,000 internet-exposed vulnerable Firebox devices
By October 20, 2025, Shadowserver Foundation scans showed that almost 76,000 WatchGuard Firebox appliances remained exposed on the public internet and vulnerable to CVE-2025-9242. Reports said the largest concentrations were in the United States and Europe and noted no active exploitation had been reported at that time.
WatchGuard discloses CVE-2025-9242 and releases patches
On September 17, 2025, WatchGuard disclosed the critical Firebox vulnerability CVE-2025-9242, an out-of-bounds write in the Fireware OS 'iked' process that can enable unauthenticated remote code execution via crafted IKEv2 packets. The company released patched Fireware versions, advised temporary workarounds for some VPN configurations, and said unsupported 11.x devices must be upgraded because they will not receive fixes.
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Sources
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Vulnerable WatchGuard Firebox appliances continue to exceed 75K
scworld.com
Open sourceWatchGuard VPN Flaw Gives Hackers Full Firewall Control
techrepublic.com
Open sourceOver 75,000 WatchGuard security devices vulnerable to critical RCE
bleepingcomputer.com
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