Multiple high-severity vulnerabilities in the WatchGuard Agent for Windows could allow malicious actors to elevate their privileges to the highest system level or disrupt critical security services.
With CVSS scores up to 8.5, these vulnerabilities pose a significant risk to organizations that rely on WatchGuard for endpoint security and threat protection.
WatchGuard Agent Flaws
Chained Vulnerabilities Lead to System Takeover
The most critical issue disclosed is a local privilege escalation vulnerability tracked under CVE-2026-6787 and CVE-2026-6788. This flaw stems from a series of chained vulnerabilities within the single WatchGuard Agent service.
An attacker with standard, low-level user access can exploit this chain to escalate their permissions to NT AUTHORITY\SYSTEM seamlessly.
Achieving SYSTEM-level access means the attacker gains complete, unrestricted control over the compromised Windows machine. With these privileges, a threat actor can install malicious software, alter core system configurations, create new administrative accounts, or access sensitive data.
WatchGuard assigned this vulnerability a high-severity CVSS score of 8.5, emphasizing the severe impact if successfully exploited by a local threat actor.
Patch Management Flaw Exposes Privilege Escalation
Another significant local privilege escalation vulnerability, identified as CVE-2026-41288, affects the patch management component of the WatchGuard Agent.
This vulnerability occurs due to incorrect permission assignments for a specific resource within the agent’s architecture.
An authenticated local user can exploit these weak permissions to bypass security boundaries and elevate their privileges to the SYSTEM level. Carrying a CVSS score of 7.3, this flaw underscores the ongoing risks posed by improper access controls in security software.
By exploiting this weakness, malware already present on the system can escalate its capabilities to execute administrative commands without restriction, paving the way for further network compromise.
Buffer Overflow Bugs Trigger Denial of Service
In addition to the severe privilege escalation risks, WatchGuard addressed two stack-based buffer overflow vulnerabilities located in the agent discovery service.
Tracked as CVE-2026-41286 (Variant B) and CVE-2026-41287 (Variant A), both of these flaws carry a CVSS score of 7.1.
These vulnerabilities allow unauthenticated attackers on the same local network to send specially crafted requests that overwhelm the system’s memory buffers. If successfully exploited, these buffer overflows will cause the WatchGuard Agent service to crash entirely, resulting in a denial-of-service (DoS) condition.
This disruption could leave the endpoint temporarily unprotected, creating a critical blind spot that allows attackers to operate without triggering security alerts.
All of these high-severity vulnerabilities impact the WatchGuard Agent on Windows versions up to and including 1.25.02.0000. Fortunately, WatchGuard has actively responded to these threats by releasing security updates.
The vendor confirms that all identified flaws, including both the privilege escalation and denial-of-service bugs, are fully resolved in WatchGuard Agent for Windows version 1.25.03.0000.
There are no practical workarounds available to mitigate these risks without applying the official patch. System administrators and cybersecurity teams, please update your WatchGuard Agents to version 1.25.03.0000 immediately to protect your Windows environments from these active attack vectors.
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