Information Disclosure in free5GC UDR Service from Vendor free5GC

CVE-2026-40247

What is CVE-2026-40247?

The UDR service in free5GC, an open-source implementation of the 5G core network, exhibits a vulnerability that allows unauthenticated attackers to access sensitive subscription data. Specifically, in versions 4.2.1 and earlier, the application fails to terminate a session upon receiving an invalid influenceId within its Traffic Influence Subscriptions handler. As a result, critical data, including Subscriber Permanent Identifiers (SUPIs), International Mobile Subscriber Identities (IMSIs), Data Network Names (DNNs), and callback URIs, can be revealed despite the initial 404 error response. This issue poses substantial risks to the integrity and confidentiality of user data in 5G services. A fix for this vulnerability was not available at the time of reporting.

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