free5GC UDR's NEF incorrectly returns 500 for missing PFD data (UDR 404) in Nnef_PfdManagement GET request

free5GC UDR is the user data repository (UDR) for free5GC, an an open-source project for 5th generation (5G) mobile core networks. Versions prior to 1.4.1 contain an Improper Error Handling vulnerability with Information Exposure. All deployments of free5GC using the Nnef_PfdManagement service may be affected. The NEF component reliably leaks internal parsing errors (e.g., invalid character 'n' after top-level value) to remote clients. This can aid attackers in fingerprinting server software and logic flows. Version 1.4.1 fixes the issue. There is no direct workaround at the application level. The recommended mitigation is to apply the provided patch.