CVE-2025-4106: WatchGuard Firebox leftover debug code vulnerability

Severity: high (CVSS 8.9 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-10-24 · updated 2026-10-08
Weakness: CWE-489

Description

An authenticated admin user with access to both the management WebUI and command line interface on a Firebox can enable a diagnostic debug shell by uploading a platform and version-specific diagnostic package and executing a leftover diagnostic command.

Affected products

WatchGuard Fireware OS: from 12.0 before 12.11.3; from 12.0 before 12.5.13 — fixed in 12.11.3, 12.5.13

How to fix

Upgrade to a fixed version: WatchGuard Fireware OS 12.11.3, 12.5.13. Check the vendor advisory for mitigations.

References

https://psirt.watchguard.com/CVE-2025-4106
https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2025-00010

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