---
id: "CVE-2026-90465"
kind: "vulnerability"
aliases: ["CVE-2026-90465"]
title: "FireCluster Sync: missing authentication lets cluster-link attacker run firewall management as root"
severity: "high"
cvss: 9.4
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "Fireware OS", "fixed": ["2026.4", "12.12.4"], "affected": ">= 2025.1, < 2026.4; >= 12.0, < 12.12.4", "ecosystem": "vendor"}, {"name": "Fireware OS (T15/T35)", "fixed": ["12.5.22"], "affected": ">= 12.0, < 12.5.22", "ecosystem": "vendor"}]
ecosystems: []
tags: ["firecluster", "firewall", "fireware", "high-availability", "infrastructure", "self-hosted", "watchguard"]
not_affected_if: ["isolated-cluster-interconnect", "not-clustered", "standalone-deployment", "standalone-firebox"]
published_at: "2026-10-27T16:17:31+00:00"
first_seen_at: "2026-10-27T16:33:07+00:00"
updated_at: "2026-10-27T16:35:33+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90465", "first_seen_at": "2026-10-27T16:33:07+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-10-27T16:35:33+00:00"}]
---

# FireCluster Sync: missing authentication lets cluster-link attacker run firewall management as root

FireCluster Sync processing does not check authentication on certain requests. An attacker on the cluster interconnect can send a crafted request and invoke privileged firewall management actions as root.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Fireware OS affected >= 2025.1, < 2026.4; >= 12.0, < 12.12.4 fixed 2026.4, 12.12.4
- vendor:Fireware OS (T15/T35) affected >= 12.0, < 12.5.22 fixed 12.5.22

## How to check

Check whether the Firebox is a FireCluster member (Web UI: System Status > FireCluster, or CLI 'show cluster'), then check Fireware version: vulnerable if >= 2025.1 and < 2026.4, or >= 12.0 and < 12.12.4; T15/T35: >= 12.0 and < 12.5.22.

## Fix

Upgrade Fireware OS to 2026.4 (2025.1 to 2026.3 branch), 12.12.4 (12.x), or 12.5.22 (T15/T35 models).

## Timeline

- 2026-10-27T16:33:07+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-90465
- 2026-10-27T16:35:33+00:00 analyst — Read WatchGuard PSIRT advisory: High 8.7 CVSS v4.0 (vendor), not exploited per vendor, sync port not stated. No PoC/mitigations found; did not search social.

## Documents

- [advisory] WatchGuard PSIRT: CVE-2026-90465 FireCluster Sync missing authentication https://psirt.watchguard.com/CVE-2026-90465

## From the sources

A missing authentication vulnerability in the FireCluster Sync processing allows an attacker positioned on the cluster interconnect, such as a compromised cluster peer or an on-path network attacker, to invoke privileged firewall management actions as root by sending a specially crafted request.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_