CVE-2026-81433#

Fireware OS Pre-Authentication Stack Buffer Overflow in fingerd Allows Remote Code Execution

High 8.7 CVSS v4.0 › Published 2026-09-29Updated 2026-09-29

Summary #

A stack-based buffer overflow vulnerability in WatchGuard Fireware OS's DHCP fingerprinting daemon (fingerd) allows an unauthenticated attacker with adjacent network access to execute arbitrary code or crash the process by sending a specially crafted DHCP packet.

Product status #

Product	Affected	Not affected
Fireware OS
Default	>= 2026.3, < 2026.3.2, >= 2025.0, < 2026.2.3, >= 12.0, < 12.12.3	>= 2026.3.2, >= 2026.2.3, >= 12.12.3

Weakness Type and Impact #

CWECWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CWECWE-121Stack-based Buffer Overflow
CWECWE-787Out-of-bounds Write
CAPECCAPEC-100Overflow Buffers

Exploitation Status #

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

Solution #

Fireware OS 2026.3.2, Fireware OS 2026.2.3, Fireware OS 12.12.3

References #

Credits #

Laurent GAFFIE, (secorizon.com)finder