CVE-2026-81433

High

Description

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.

SeverityHigh

CVSS8.7

Exploit probability—

ProductFireware OS

PublishedSep 30, 2026

First seenSep 30, 2026

Weakness typeCWE-120CWE-120 CWE-121CWE-121 CWE-787Out-of-bounds write

How to fix

Update

WatchGuard Fireware OS2026.3.2, 2026.2.3, 12.12.3 or later

Vendor advisories

psirt.watchguard.com/CVE-2026-81433

Affected products

Product	Affected versions	Fixed in
WatchGuard Fireware OS	2026.3 ≤ v < 2026.3.2, 2025.0 ≤ v < 2026.2.3, 12.0 ≤ v < 12.12.3	2026.3.2, 2026.2.3, 12.12.3

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