Check Point Advisories

Fortinet FortiWeb Out Of Bounds Write (CVE-2026-40688)

Vulnerability
Protection

Check Point Reference:	CPAI-2026-4584
Date Published:	17 May 2026
Severity:	High
Last Updated:	Sunday 17 May, 2026
Source:
Industry Reference:	CVE-2026-40688
Protection Provided by:	Security Gateway R81, R80, R77, R75
Who is Vulnerable?	Fortinet FortiWeb 7.4.0 and later, prior to 7.4.12 Fortinet FortiWeb 7.6.0 and later, prior to 7.6.7 Fortinet FortiWeb 8.0.0 and later, prior to 8.0.4
Vulnerability Description	An out-of-bounds write vulnerability in Fortinet FortiWeb allows remote privileged attackers to execute arbitrary code or commands via crafted HTTP requests.

Protection Overview

This protection detects attempts to exploit this vulnerability.

In order for the protection to be activated, update your Security Gateway product to the latest IPS update. For information on how to update IPS, go to SBP-2006-05, click on Protection tab and select the version of your choice.

Security Gateway R81 / R80 / R77 / R75

In the IPS tab, click Protections and find the Fortinet FortiWeb Out Of Bounds Write (CVE-2026-40688) protection using the Search tool and Edit the protection's settings.
Install policy on all Security Gateways.

This protection's log will contain the following information:

Attack Name: Application Servers Protection Violation.
Attack Information: Fortinet FortiWeb Out Of Bounds Write (CVE-2026-40688)