WatchGuard Fireware OS contains an out-of-bounds write (CWE-787) in the iked process that a remote, unauthenticated attacker can trigger to execute arbitrary code on the appliance. The flaw is reachable via the mobile user VPN with IKEv2 and via branch office VPNs using IKEv2 to a dynamic gateway peer; devices whose IKEv2 configurations were deleted may remain vulnerable if a branch office VPN to a static gateway peer is still configured. Successful exploitation yields full system compromise, reflected in the CVSS v4.0 base score of 9.3 (network vector, no privileges or user interaction, high impact on confidentiality, integrity and availability). WatchGuard Firebox appliances with IKEv2 VPN services are affected, with public reporting citing roughly 54,000 internet-exposed Fireboxes; the issue was added to CISA's Known Exploited Vulnerabilities catalog on 2025-11-12, a public proof-of-concept exploit exists, and headlines indicate use in ransomware attacks (KEV ransomware field is listed as unknown). EPSS assigns a 91.3% probability of exploitation within 30 days (100th percentile), so remediation urgency is high.
What to do: Apply the patched Fireware OS release per WatchGuard's security advisory immediately (exact fixed version numbers are not provided in the source data); the KEV listing makes BOD 22-01 remediation timelines mandatory for U.S. federal agencies. As an interim mitigation, restrict or disable IKEv2 VPN exposure — mobile user VPN with IKEv2 and branch office VPN IKEv2, including residual static-peer BOVPN configurations on devices that previously had IKEv2 configured — to trusted sources only. Administrators should audit configuration history to identify Fireboxes with prior IKEv2 mobile VPN or dynamic-peer BOVPN setups, since these may remain vulnerable even after the configs were deleted.
Affected
WatchGuard Firebox appliances running Fireware OS (iked process)
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Estimated exposure
large≈54,000 internet-exposed Fireboxes (public scan figure cited in coverage) — Security coverage of the CISA listing cites approximately 54,000 Fireboxes exposed, and the flaw only affects units with IKEv2 VPN configurations, so the true population is likely a subset of that scanned total.
Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.
Description
An Out-of-bounds Write vulnerability in the WatchGuard Fireware OS iked process may allow a remote unauthenticated attacker to execute arbitrary code. This vulnerability affects both the mobile user VPN with IKEv2 and the branch office VPN using IKEv2 when configured with a dynamic gateway peer. If the Firebox was previously configured with the mobile user VPN with IKEv2 or a branch office VPN using IKEv2 to a dynamic gateway peer, and both of those configurations have since been deleted, that Firebox may still be vulnerable if a branch office VPN to a static gateway peer is still configured.
CISA Known Exploited Vulnerability
Affected
WatchGuard Firebox
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA confirms ransomware gangs are exploiting critical unauthenticated RCE CVE-2025-14733 in WatchGuard Firebox firewalls, with roughly 9,000 devices still unpatched.
CVE-2025-14733 is an out-of-bounds write in WatchGuard Fireware OS allowing unauthenticated remote code execution, exploitable on firewalls configured for IKEv2 VPN and potentially even after the configuration was deleted if a static branch-office VPN peer remains. WatchGuard released patches in December and confirmed in-the-wild exploitation; Shadowserver found over 115,000 exposed Fireboxes at the time, with nearly 9,000 still unpatched after nine months. CISA added the flaw to its Known Exploited Vulnerabilities catalog in December under BOD 22-01 and on Thursday confirmed ransomware gangs are now exploiting it, without providing campaign details. WatchGuard serves more than 250,000 small and mid-sized companies through 17,000+ security resellers and service providers.