CVE-2026-78011

Fireware OS Integer Underflow in Iked Allows Unauthenticated Denial of Service (DoS)

High 8.7 CVSS v4.0 › Published 2026-08-27Updated 2026-08-27

Summary #

An integer underflow vulnerability in the WatchGuard Fireware OS iked process allows a remote unauthenticated attacker to create a Denial of Service (DoS) condition in VPN processing by sending specially crafted network traffic.

Impact: A remote unauthenticated attacker can send a single crafted UDP IKEv1 packet to crash iked, resulting in a denial-of-service condition, confirmed via proof-of-concept testing. Depending on memory layout, the uncontrolled write into adjacent stack, heap, or global memory may also provide a path to remote code execution.

Product status #

ProductAffectedNot affected
Fireware OS
Default >= 2025.0, < 2026.2.2, >= 12.0, < 12.12.2>= 2026.2.2, >= 12.12.2
T15/T35 >= 12.0, < 12.5.20>= 12.5.20

Weakness Type and Impact #

Exploitation Status #

WatchGuard is not aware of any exploitation of this vulnerability in the wild.

Solution #

Fireware OS 2026.2.2, Fireware OS 12.12.2, Fireware OS 12.5.20

References #

    Credits #

    • Discovered Internally by WatchGuard AI Security Researchfinder