CVE-2026-8247: WatchGuard Firebox admd Out of Bounds Write Vulnerability

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-03 · updated 2026-10-25
Weakness: CWE-120

Description

An Out-of-bounds Write vulnerability in WatchGuard Fireware OS may allow an unauthenticated attacker on the same local network segment to execute arbitrary code. This vulnerability affects Fireware OS 11.0 up to and including 11.12.4_Update1, 12.0 up to and including 12.12 and 2025.1 up to and including 2026.2.

Affected products

WatchGuard Fireware OS: from 11.0.0 before 11.12.4; from 12.5 before 12.5.19; from 2025.1 before 2026.2.1; from 12.0 before 12.12.1; 11.12.4, 11.12.4-u1 — fixed in 11.12.4, 12.5.19, 2026.2.1, 12.12.1

How to fix

Upgrade to a fixed version: WatchGuard Fireware OS 11.12.4, 12.5.19, 2026.2.1, 12.12.1. Check the vendor advisory for mitigations.

References

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