Free5GC up to 1.4.2 subs-to-notify information disclosure

Summaryinfo

A vulnerability was found in Free5GC up to 1.4.2. It has been declared as problematic. This affects an unknown part of the file /nudr-dr/v2/application-data/influenceData/subs-to-notify. Executing a manipulation can lead to information disclosure. This vulnerability is tracked as CVE-2026-40245. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability classified as problematic was found in Free5GC up to 1.4.2. This vulnerability affects some unknown processing of the file /nudr-dr/v2/application-data/influenceData/subs-to-notify. The manipulation with an unknown input leads to a information disclosure vulnerability. The CWE definition for the vulnerability is CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. As an impact it is known to affect confidentiality. CVE summarizes:

Free5GC is an open-source Linux Foundation project for 5th generation (5G) mobile core networks. Versions 4.2.1 and below contain an information disclosure vulnerability in the UDR (Unified Data Repository) service. The handler for GET /nudr-dr/v2/application-data/influenceData/subs-to-notify sends an HTTP 400 error response when required query parameters are missing but does not return afterward. Execution continues into the processor function, which queries the data repository and appends the full list of Traffic Influence Subscriptions, including SUPI/IMSI values, to the response body. An unauthenticated attacker with network access to the 5G Service Based Interface can retrieve stored subscriber identifiers with a single parameterless HTTP GET request. The SUPI is the most sensitive subscriber identifier in 5G networks, and its exposure undermines the privacy guarantees of the 3GPP SUCI concealment mechanism at the core network level. A similar bypass exists when sending a malformed snssai parameter due to the same missing return pattern.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-40245 since 04/10/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 04/16/2026). The MITRE ATT&CK project declares the attack technique as T1592.

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

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Productinfo

Name

• Free5GC

Version

• 1.4.0
• 1.4.1
• 1.4.2

Website

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

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