CVE-2026-86128

High

Description

A NULL pointer dereference vulnerability in Fireware OS's NetFlow packet-processing feature allows a remote, unauthenticated attacker to cause a denial of service by sending a specially crafted IPv6 packet.

SeverityHigh

CVSS7.5

Exploit probability—

ProductWatchguard Fireware

PublishedSep 30, 2026

First seenSep 30, 2026

Weakness typeCWE-476NULL pointer dereference

How to fix

Update

watchguard fireware12.5.21, 12.12.3, 2026.2.3, 2026.3.2 or later

Vendor advisories

psirt.watchguard.com/CVE-2026-86128

Affected products

Product	Affected versions	Fixed in
watchguard fireware	12.0 ≤ v < 12.5.21, 12.12 ≤ v < 12.12.3, 2025.0 ≤ v < 2026.2.3, 2026.3 ≤ v < 2026.3.2	12.5.21, 12.12.3, 2026.2.3, 2026.3.2

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