Free5GC up to 1.4.2 UDR Service notificationUri improper authorization

Summaryinfo

A vulnerability described as critical has been identified in Free5GC up to 1.4.2. Impacted is an unknown function of the component UDR Service. The manipulation of the argument notificationUri results in improper authorization. This vulnerability was named CVE-2026-40248. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as critical, was found in Free5GC up to 1.4.2. Affected is an unknown code block of the component UDR Service. The manipulation of the argument notificationUri with an unknown input leads to a improper authorization vulnerability. CWE is classifying the issue as CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

free5GC is an open-source implementation of the 5G core network. In versions 4.2.1 and below of the UDR service, the handler for creating or updating Traffic Influence Subscriptions checks whether the influenceId path segment equals subs-to-notify, but does not return after sending the HTTP 404 response when validation fails. Execution continues and the subscription is created or overwritten regardless. An unauthenticated attacker with access to the 5G Service Based Interface can create or overwrite arbitrary Traffic Influence Subscriptions, including injecting attacker-controlled notificationUri values and arbitrary SUPIs, by supplying any value for the influenceId path segment. A patched version was not available at the time of publication.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-40248 since 04/10/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 04/20/2026). This vulnerability is assigned to T1548.002 by the MITRE ATT&CK project.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at CNNVD (CNNVD-202604-3429). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Name

• Free5GC

Version

• 1.4.0
• 1.4.1
• 1.4.2

Website

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

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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