Check Point Advisories

IKE Unsigned Underflow

Vulnerability
Protection

Check Point Reference:	CPAI-2026-4368
Date Published:	11 May 2026
Severity:	High
Last Updated:	Monday 11 May, 2026
Source:
Protection Provided by:	Security Gateway R81, R80, R77, R75
Who is Vulnerable?
Vulnerability Description	An unsigned underflow vulnerability occurs when an arithmetic operation on an unsigned integer produces a value smaller than its minimum representable value. This can lead to wrapping around to a very large value, potentially causing unexpected behavior like memory corruption in software. Attackers may exploit this flaw to bypass checks, manipulate logic, or trigger crashes.

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 IKE Unsigned Underflow 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: IKE Unsigned Underflow