---
id: CVE-2026-93857
title: >-
  Fireware OS Pre-Authentication Stack Buffer Overflow in SIP Proxy Allows
  Remote Code Execution
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.
severity: critical
cvss: 9.2
cvssVector: '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'
cvssSource: cna
cwe:
  - CWE-120
  - CWE-121
  - CWE-787
vendor: WatchGuard
product: Fireware OS
affected:
  - fireware_os >= 2025.1 < 2026.4
  - fireware_os >= 12.0 < 12.12.4
  - fireware_os >= 12.0 < 12.5.22
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-29T03:56:44.782585Z'
published: '2026-10-27'
updated: '2026-10-29'
sourceUpdated: '2026-10-29T10:45:46.751Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-93857'
references:
  - url: 'https://psirt.watchguard.com/CVE-2026-93857'
tags:
  - cve.org
epss: 0.00471
epssPercentile: 0.4077
ingestedAt: '2026-10-27T16:11:59.475Z'
---

## Overview

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.

## Affected

- `fireware_os >= 2025.1 < 2026.4`
- `fireware_os >= 12.0 < 12.12.4`
- `fireware_os >= 12.0 < 12.5.22`

## Remediation

Fireware OS 2026.4, Fireware OS 12.12.4, Fireware OS 12.5.22