CVE-2026-86105: Fireware OS Improper Authorization in Access Portal Reverse Proxy

Severity: high (CVSS 7.1 v3.1)
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: 2026-09-30 · updated 2026-10-06
Weakness: CWE-22

Description

An improper authorization vulnerability in Fireware OS's Access Portal reverse proxy allows an authenticated, low-privileged Access Portal user to access other web applications they are not authorized for by sending a specially crafted request for a different resource which they are authorized to access.

Affected products

WatchGuard Fireware OS: from 12.0 before 12.5.21; from 12.12 before 12.12.3; from 2025.0 before 2026.2.3; from 2026.3 before 2026.3.2 — fixed in 12.12.3, 12.5.21, 2026.2.3, 2026.3.2

How to fix

Upgrade to a fixed version: WatchGuard Fireware OS 12.12.3, 12.5.21, 2026.2.3, 2026.3.2. Check the vendor advisory for mitigations.

References

https://psirt.watchguard.com/CVE-2026-86105

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