CVE-2026-13086: Fireware OS Stack-Based Buffer Overflow in Mobile Security epm Endpoint

Severity: critical (CVSS 9.3 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-28 · updated 2026-09-03
Weakness: CWE-121

Description

A stack-based buffer overflow in the epm (Endpoint Protection Manager) service used by the deprecated Mobile Security feature in WatchGuard Fireware OS allows an unauthenticated remote attacker to execute arbitrary code.

Affected products

WatchGuard Fireware OS: from 2025.0 before 2026.2.2; from 12.0 before 12.12.2; from 2026.3 before 2026.3.1; from 12.0 before 12.5.20 — fixed in 12.12.2, 12.5.20, 2026.2.2, 2026.3.1

How to fix

Upgrade to a fixed version: WatchGuard Fireware OS 12.12.2, 12.5.20, 2026.2.2, 2026.3.1. Check the vendor advisory for mitigations.

References

https://psirt.watchguard.com/CVE-2026-13086

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