CVE-2026-93866 WatchGuard Fireware OS - Integer Overflow

WatchGuard Fireware OS Access Portal contains an integer overflow caused by improper WebSocket connection handling, letting remote unauthenticated attackers write beyond heap buffer bounds, exploit requires Access Portal enabled.

CVSS base score 9.2 /10
Critical
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.45% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Integer Overflow
Impact
Remote Code Execution
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
27 October 2026
Updated
29 October 2026
Weakness
CWE-190

Vendor fix

Update to the latest version of WatchGuard Fireware OS.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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