CVE-2026-93857#

Fireware OS Pre-Authentication Stack Buffer Overflow in SIP Proxy Allows Remote Code Execution

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

Summary #

A stack-based buffer overflow vulnerability in Fireware OS's SIP proxy allows a remote, unauthenticated attacker to execute arbitrary code by sending a specially crafted request through a policy that uses the SIP proxy.

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 #

The exploit for this vulnerability requires a SIP proxy configured on the Firebox.

Weakness Type and Impact #

CWECWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CWECWE-121Stack-based Buffer Overflow
CWECWE-787Out-of-bounds Write
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