CVE-2026-13371: WatchGuard Fireware

Medium severity, CVSS 4.9. EPSS: 0.6% chance of exploitation in the next 30 days.

An authenticated administrator can trigger a denial-of-service condition in the Fireware Management Web UI by sending malformed or crafted data to the put_data endpoint, which performs unsafe deserialization of the attacker-supplied input.

Affected products

• WatchGuard Fireware: from 2025.1, before 2026.2.1 (fixed in 2026.2.1); from 12.5, before 12.5.19 (fixed in 12.5.19); from 12.0, before 12.12.1 (fixed in 12.12.1)

Published 2026-07-03. Last modified 2026-08-28.