Check Point Advisories

free5GC Insecure Deserialization (CVE-2026-40343)

Vulnerability
Protection

Check Point Reference:	CPAI-2026-3422
Date Published:	30 Apr 2026
Severity:	Medium
Last Updated:	Thursday 30 April, 2026
Source:
Industry Reference:	CVE-2026-40343
Protection Provided by:	Security Gateway R81, R80, R77, R75
Who is Vulnerable?	free5GC 4.2.1 and prior free5GC UDR 1.4.2 and prior
Vulnerability Description	An insecure deserialization vulnerability in free5GC products allows remote attackers to create Policy Data notification subscriptions with invalid, empty, or partially processed input by exploiting deserialization errors in the UDR service.

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 free5GC Insecure Deserialization (CVE-2026-40343) 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: free5GC Insecure Deserialization (CVE-2026-40343)