Vulnerability · Published Oct 27, 2026 · Assigned by WatchGuard

CVE-2026-93862Fireware OS Out-of-Bounds Read in FireCluster Sync Allows Denial of Service

High 7.2

In plain English

A high-severity out-of-bounds read in Fireware OS from WatchGuard. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 6% of all known vulnerabilities).

Severity (CVSS 4.0)7.2High

Exploit odds (30 days)0.2%top 94.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

An out-of-bounds read 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 repeatedly crash the firewall's cluster synchronization process by sending specially crafted network traffic, resulting in a sustained denial of service.

Affected products (as reported)

Vendor	Product	Versions
WatchGuard	Fireware OS	2025.1 – before 2026.412.0 – before 12.12.4
WatchGuard	Fireware OS	12.0 – before 12.5.22

Weakness: CWE-125, CWE-129, CWE-787, CWE-823 · Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

References

https://psirt.watchguard.com/CVE-2026-93862 vendor-advisory