Firebox and Fireware OS
CVE-2024-6594: WatchGuard Firebox Single Sign-On Client Denial-of-Service
Improper Handling of Exceptional Conditions vulnerability in the WatchGuard Single Sign-On Client on Windows causes the client to crash while handling malformed commands.
Published
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| SSO Client (Windows) 12.0 to 12.7 | Upgrade past 12.7; see the advisory |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
Improper Handling of Exceptional Conditions vulnerability in the WatchGuard Single Sign-On Client on Windows causes the client to crash while handling malformed commands. An attacker with network access to the client could create a denial of service condition for the Single Sign-On service by repeatedly issuing malformed commands.
Workarounds
An attacker must have already established network access to exploit this vulnerability. WatchGuard recommends using Windows Firewall rules to restrict TCP port 4116 network access to the Single Sign-On Client to only allow connections from the Authentication Gateway (SSO Agent). Windows administrators can use Group Policy objects to add Windows firewall rules to their endpoints.
Exploitation
WatchGuard is not aware of any exploitation of this vulnerability in the wild.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 13 Oct 2026.