CVE-2026-19318 in Fireware OS
Summary
by MITRE • 08/28/2026
A stack-based buffer overflow vulnerability in the WatchGuard Fireware OS iked process allows a remote unauthenticated attacker to execute arbitrary code by sending specially crafted network traffic.
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Analysis
by VulDB Data Team • 08/28/2026
The identified vulnerability represents a critical security flaw within the Internet Key Exchange daemon, commonly referred to as ike or ike2, which is an integral component of the WatchGuard Fireware operating system. This process is responsible for managing the establishment, modification, and termination of Security Associations in IPsec tunnels, handling complex cryptographic negotiations between network endpoints. The core technical issue stems from a stack-based buffer overflow condition located within this service. Such vulnerabilities typically arise when software fails to properly validate the length or boundaries of input data before copying it into a fixed-size memory buffer allocated on the call stack. In this specific instance, an attacker can exploit this flaw by transmitting specially crafted network packets that contain oversized or malformed IKE messages. When the ike process attempts to parse these malicious inputs without adequate bounds checking, the excess data overwrites adjacent memory locations on the stack, potentially corrupting critical control structures such as return addresses and saved frame pointers.
The operational impact of this vulnerability is severe due to its remote nature and lack of authentication requirements. Because the flaw exists in a network-facing service that handles initial connection requests for IPsec tunnels, an unauthenticated attacker can trigger the exploit from any location on the internet or internal network segment where the firewall is reachable. Successful exploitation allows the execution of arbitrary code with the privileges of the ike process, which typically runs as root or with high-level system permissions to manage cryptographic keys and tunnel configurations. This capability enables attackers to gain full control over the affected device, potentially leading to a complete compromise of the network perimeter. The attacker could install backdoors, exfiltrate sensitive data, pivot into internal networks protected by the firewall, or disrupt critical security services by terminating active tunnels or manipulating routing tables.
From a classification perspective, this vulnerability aligns with Common Weakness Enumeration identifier CWE-120, which describes buffer copy without checking size limits, specifically manifesting as a stack-based overflow. In terms of adversary tactics and techniques, the exploitation vector corresponds to ATT&CK technique T1190, Exploit Public-Facing Application, where attackers leverage vulnerabilities in services exposed to external networks. Furthermore, the initial access phase involves sending crafted network traffic, which maps to ATT&CK tactic TA0001, Initial Access, specifically through techniques like Remote Services or Network Service Scanning and exploitation. The persistence of such an exploit is particularly dangerous as it compromises a foundational security control, effectively neutralizing one of the primary defenses against external threats.
Mitigation strategies must address both immediate remediation and long-term hardening practices. The most effective solution is to apply the vendor-provided software update or patch that corrects the input validation logic within the ike process, ensuring that all incoming IKE messages are strictly validated for size and structure before processing. Until patches can be deployed, network administrators should consider implementing strict access control lists on upstream routers or firewalls to restrict UDP port 500 and 4500 traffic to only known, trusted IP addresses if possible, although this may impact legitimate remote access functionality. Additionally, enabling deep packet inspection features that can detect anomalous IKE payloads might provide a layer of defense against exploitation attempts. Regular vulnerability scanning and continuous monitoring for unusual network activity related to IKE negotiations are essential components of a robust security posture to detect potential exploitation attempts early.