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CriticalVulnerabilityCVE-2026-90465updated 27 Oct 2026, 19:35 UTC

FireCluster Sync lets unauthenticated attackers on the cluster link run privileged firewall actions

Someone who can reach the link between firewalls in a cluster can send a crafted message and make the firewall do privileged administrative actions, with the highest system rights. No password is needed to do this.

Official, 2 sources
SeverityCriticalCVSS 9.4 of 10
Being exploited?UnclearNo reports either way yet
Fix available?UnclearNo fixed version published in the sources yet
How sure is this?Official, 2 sourcesBacked by an official source

How the attack works simplified

  1. 1Attacker on linkCompromised peer or on-path network attacker
  2. 2Cluster interconnectSends a specially crafted sync request
  3. 3FireCluster SyncAccepts request without authentication
  4. 4Firewall as rootPrivileged management actions executed
  5. ResultAttacker controls the firewall as root

What happened

The FireCluster Sync processing component lacks authentication, allowing an attacker on the cluster interconnect to invoke privileged firewall management actions as root via a specially crafted request.

Why it is dangerous: An attacker who reaches the cluster interconnect could take full control of the firewall, changing rules or disabling protections, and could pivot into the networks it protects. Critical severity (CVSS 9.4).

Are you affected?

You are affected if you run FireCluster Sync in a firewall cluster and an attacker could reach the cluster interconnect, such as through a compromised cluster peer or an on-path network position.

What to do

  1. Check the GitHub advisory and vendor site for a fixed FireCluster Sync version and apply it as soon as it is released
  2. Restrict the cluster interconnect so only the intended cluster peers can reach it, and isolate it from user and internet networks
  3. Monitor the cluster interconnect for unexpected or unusual sync traffic

Timeline

  1. 27 Oct 2026, 16:17 UTC
    Publicly disclosed
  2. 27 Oct 2026, 16:17 UTC
    Reported by NVD · NVD
  3. 27 Oct 2026, 16:20 UTC
    Picked up by Zero Radar
  4. 27 Oct 2026, 19:35 UTC
    GitHub Advisory reported on it · GitHub Advisory

Sources 2 reports, oldest first

Official vendor, government CERT or advisory database

Technical details

ID
CVE-2026-90465 · GHSA-rwrf-f344-f6wx
CVSS
9.4 / 10
EPSS
0.2% chance of exploitation within 30 days
Disclosed
27 Oct 2026, 16:17 UTC
On Zero Radar
27 Oct 2026, 16:20 UTC (3 min after disclosure)
Last change
27 Oct 2026, 19:35 UTC

The plain-language parts and the attack diagram were written by an AI model (anthropic/claude-haiku-5.5) from the sources above. Facts like versions, exploitation and dates come from the sources themselves. How Zero Radar works

FireCluster Sync lets unauthenticated attackers on the cluster link run privileged firewall actions · Zero Radar