---
id: CVE-2025-53843
title: >-
  A stack-based buffer overflow vulnerability in Fortinet FortiOS 7.6.0 through
  7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2 all versions, FortiOS 7.0 all
  versions, FortiOS 6.4 all versions allows attacker to execute unauthorized
  code o…
summary: >-
  A stack-based buffer overflow vulnerability in Fortinet FortiOS 7.6.0 through
  7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2 all versions, FortiOS 7.0 all
  versions, FortiOS 6.4 all versions allows attacker to execute unauthorized
  code o…
severity: medium
cvss: 6.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:W/RC:C'
cvssSource: cna
cwe:
  - CWE-121
vendor: Fortinet
product: FortiOS
affected:
  - FortiOS >= 7.6.0 <= 7.6.3
  - FortiOS >= 7.4.0 <= 7.4.8
  - FortiOS >= 7.2.0 <= 7.2.12
  - FortiOS >= 7.0.0 <= 7.0.18
  - FortiOS >= 6.4.0 <= 6.4.16
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2025-11-19T04:55:32.869143Z'
published: '2025-11-18'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T01:09:15.880Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-53843'
references:
  - url: 'https://fortiguard.fortinet.com/psirt/FG-IR-25-358'
    label: 'https://fortiguard.fortinet.com/psirt/FG-IR-25-358'
tags:
  - cve.org
epss: 0.00589
epssPercentile: 0.46917
ingestedAt: '2026-10-15T05:52:46.070Z'
---

## Overview

A stack-based buffer overflow vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2 all versions, FortiOS 7.0 all versions, FortiOS 6.4 all versions allows attacker to execute unauthorized code or commands via specially crafted packets

## Affected

- `FortiOS >= 7.6.0 <= 7.6.3`
- `FortiOS >= 7.4.0 <= 7.4.8`
- `FortiOS >= 7.2.0 <= 7.2.12`
- `FortiOS >= 7.0.0 <= 7.0.18`
- `FortiOS >= 6.4.0 <= 6.4.16`

## Remediation

Fortinet remediated this issue in FortiSASE version 25.3.c and hence customers do not need to perform any action.
Fortinet remediated this issue in FortiEdgeCloud version 25.3 and hence customers do not need to perform any action.
Upgrade to FortiSwitchManager version 7.2.7 or above
Upgrade to FortiSwitchManager version 7.0.6 or above
Upgrade to upcoming  FortiOS version 8.0.0 or above
Upgrade to FortiOS version 7.6.4 or above
Upgrade to FortiOS version 7.4.9 or above