CVE-2026-78010 in Fireware
Summary
by MITRE • 08/28/2026
A stack-based buffer overflow vulnerability in the WatchGuard Fireware OS iked process iallows a remote unauthenticated attacker to create a Denial of Service (DoS) condition in VPN processing by sending specially crafted network traffic.
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Analysis
by VulDB Data Team • 08/28/2026
The identified security flaw resides within the Internet Key Exchange daemon, commonly referred to as ike or ipsec-tools, which is an integral component of the WatchGuard Fireware operating system responsible for managing IPsec tunnel negotiations and key exchanges. This specific vulnerability manifests as a stack-based buffer overflow, a classic memory corruption error where data written to a fixed-size buffer on the call stack exceeds its allocated boundaries. The root cause typically involves insufficient validation or bounds checking when processing incoming network packets destined for IKE negotiation endpoints. Because this service handles cryptographic handshake protocols essential for establishing secure virtual private networks, it is frequently exposed to untrusted external traffic, making it an attractive target for exploitation by remote adversaries seeking to disrupt critical infrastructure services without requiring prior authentication credentials.
From a technical perspective, the overflow allows an attacker to overwrite adjacent memory locations on the stack, potentially including return addresses or function pointers that dictate the flow of execution within the ike process. By carefully crafting network traffic payloads containing maliciously sized or formatted data fields, an unauthenticated remote actor can manipulate these overwritten values to redirect program control flow or simply cause a segmentation fault due to invalid memory access patterns. In this specific instance, the primary consequence is not arbitrary code execution but rather a denial of service condition affecting VPN processing capabilities. When the ike process crashes or becomes unstable due to the corrupted stack state, it fails to respond to legitimate IKE requests, thereby preventing new IPsec tunnels from being established and potentially disrupting existing connections that rely on periodic re-keying mechanisms managed by this daemon.
The operational impact of this vulnerability is significant for organizations relying on WatchGuard firewalls for secure remote access or site-to-site connectivity. A successful exploitation results in the degradation or complete cessation of VPN services, leading to a loss of availability for users attempting to connect remotely and potentially interrupting inter-office communications that depend on encrypted tunnels. Since the attack requires no authentication, it can be launched by any external actor with network reachability to the firewall's public interfaces configured for IKE traffic. This aligns closely with Common Weakness Enumeration identifier CWE-121, which defines stack-based buffer overflow as a critical memory safety issue, and maps directly to MITRE ATT&CK technique T1498, Network Denial of Service, specifically under the sub-technique of resource exhaustion through protocol abuse. The lack of authentication requirement further elevates the risk profile, placing it in high-severity categories within most vulnerability scoring systems due to its ease of exploitation and broad impact on service availability.
Mitigation strategies must address both immediate remediation and long-term architectural resilience. The primary defense is the timely application of vendor-provided patches or firmware updates that correct the buffer handling logic within the ike process, ensuring strict input validation and bounds checking are enforced for all incoming IKE packets. Administrators should verify their current software version against official security advisories released by WatchGuard to determine if they are affected. In environments where immediate patching is not feasible due to operational constraints or testing requirements, network-level mitigations can be employed as temporary countermeasures. This includes configuring access control lists on upstream routers or next-generation firewalls to restrict IKE traffic sources to only known and trusted IP addresses, thereby reducing the attack surface exposed to unauthenticated actors. Additionally, enabling rate limiting for IKE negotiation requests can help mitigate volumetric aspects of such attacks by preventing a single source from overwhelming the service with crafted packets designed to trigger the overflow condition repeatedly.