CVE-2026-93866#

Fireware OS Pre-Authentication Integer Overflow in Access Portal Allows Out-of-Bounds Write

Critical 9.2 CVSS v4.0 › Published 2026-10-27Updated 2026-10-27

Summary #

An integer overflow vulnerability in the WebSocket connection handling used by WatchGuard Fireware OS's Access Portal allows a remote, unauthenticated attacker to write beyond the bounds of a heap buffer by sending a specially crafted request while the Access Portal feature is enabled.

Product status #

Product	Affected	Not affected
Fireware OS
Default	>= 2025.1, < 2026.4, >= 12.0, < 12.12.4	>= 2026.4, >= 12.12.4
T15/T35	>= 12.0, < 12.5.22	>= 12.5.22

Required Configuration for Exposure #

This vulnerability affects Firebox deployments with the Access Portal enabled.

Weakness Type and Impact #

CWECWE-190Integer Overflow or Wraparound
CWECWE-288Authentication Bypass Using an Alternate Path or Channel
CWECWE-787Out-of-bounds Write
CAPECCAPEC-92Forced Integer Overflow
CAPECCAPEC-100Overflow Buffers

Exploitation Status #

WatchGuard is not aware of any exploitation of this vulnerability in the wild.

Solution #

Fireware OS 2026.4, Fireware OS 12.12.4, Fireware OS 12.5.22

References #

Credits #

Laurent GAFFIE , secorizon.comfinder