CVE-2026-8247 in Fireware OS
Summary
by MITRE • 07/03/2026
An Out-of-bounds Write vulnerability in WatchGuard Fireware OS may allow an unauthenticated attacker on the same local network segment to execute arbitrary code.
This vulnerability affects Fireware OS 11.0 up to and including 11.12.4_Update1, 12.0 up to and including 12.12 and 2025.1 up to and including 2026.2.
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Analysis
by VulDB Data Team • 07/03/2026
This out-of-bounds write vulnerability in WatchGuard Fireware OS represents a critical security flaw that enables remote code execution through unauthenticated network access. The vulnerability stems from improper input validation within the operating system's processing mechanisms, specifically affecting versions spanning multiple release branches including 11.0 through 11.12.4_Update1, 12.0 through 12.12, and 2025.1 through 2026.2. Attackers exploiting this weakness can manipulate memory allocation patterns to write data beyond the bounds of allocated buffers, potentially overwriting critical system structures or executable code segments.
The technical exploitation of this vulnerability occurs when an attacker sends specially crafted network packets to a targeted Fireware OS device within the same local network segment. This type of attack falls under the category of local network-based privilege escalation and can be classified as a CWE-787 Out-of-bounds Write vulnerability according to the Common Weakness Enumeration standards. The flaw represents a fundamental breakdown in memory safety controls that allows attackers to bypass authentication requirements entirely, making it particularly dangerous in network security contexts where unauthorized access can lead to complete system compromise.
From an operational impact perspective, this vulnerability creates significant risk for organizations relying on WatchGuard firewalls for network protection. The ability to execute arbitrary code without authentication essentially grants attackers full control over affected devices, potentially enabling them to establish persistent backdoors, redirect traffic through malicious proxies, or use compromised systems as launching points for broader network attacks. This aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1566.002 for spearphishing attachment, as compromised firewalls can serve as both attack vectors and exfiltration points for sensitive data.
Organizations must prioritize immediate remediation efforts by upgrading to patched versions of Fireware OS that address this memory safety vulnerability. The recommended mitigation strategy involves implementing network segmentation controls to limit local network access to firewall devices where possible, deploying intrusion detection systems to monitor for suspicious packet patterns, and establishing robust patch management procedures. Additionally, organizations should consider implementing network access control measures such as 802.1X authentication or MAC address filtering to reduce the attack surface available to potential adversaries attempting exploitation of this vulnerability.