Free5GC up to 1.4.1 UDM Service /sdm-subscriptions DataChangeNotificationProcedure missing default case in switch statement

Summaryinfo

A vulnerability marked as problematic has been reported in Free5GC up to 1.4.1. This affects the function DataChangeNotificationProcedure of the file /sdm-subscriptions of the component UDM Service. The manipulation leads to missing default case in switch statement. This vulnerability is listed as CVE-2026-33064. The attack may be initiated remotely. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Free5GC up to 1.4.1 and classified as problematic. This issue affects the function DataChangeNotificationProcedure of the file /sdm-subscriptions of the component UDM Service. The manipulation with an unknown input leads to a missing default case in switch statement vulnerability. Using CWE to declare the problem leads to CWE-478. The code does not have a default case in an expression with multiple conditions, such as a switch statement. Impacted is availability. The summary by CVE is:

Free5GC is an open-source Linux Foundation project for 5th generation (5G) mobile core networks. Versions prior to 1.4.2 are vulnerable to procedure panic caused by Nil Pointer Dereference in the /sdm-subscriptions endpoint. A remote attacker can cause the UDM service to panic and crash by sending a crafted POST request to the /sdm-subscriptions endpoint with a malformed URL path containing path traversal sequences (../) and a large JSON payload. The DataChangeNotificationProcedure function in notifier.go attempts to access a nil pointer without proper validation, causing a complete service crash with "runtime error: invalid memory address or nil pointer dereference". Exploitation would result in UDM functionality disruption until recovery by restart. This issue has been fixed in version 1.4.2.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-33064 since 03/17/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 303461 (Linux Distros Unpatched Vulnerability : CVE-2026-33064), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.4.2 eliminates this vulnerability. Applying the patch 65d7070f4bfd016864cbbaefbd506bbc85d2fa92 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (303461). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

• Free5GC

Version

• 1.4.0
• 1.4.1

License

• open-source

Website

• Product: https://github.com/free5gc/free5gc/

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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