The vulnerability is a NULL pointer dereference in the UDMC registration handler component of free5gc version 4.0.1. An attacker can send a crafted registration message that causes the service to dereference a null pointer, leading to a crash and resulting in a denial of service. This flaw is a classic example of CWE‑476.

The affected product is the free5gc open‑source 5G core implementation, specifically version 4.0.1. No official CNA vendors are listed, but the known reference indicates the issue exists in the free5gc codebase. Systems running this version without the fix are susceptible to the described DoS.

The CVSS score of 7.5 demonstrates that the vulnerability carries high severity, while an EPSS score of less than 1% indicates a low probability of active exploitation at present. The vulnerability is not listed in CISA's KEV catalog, suggesting no publicly observed exploits yet. Nevertheless, the DoS impact could be significant for networks relying on free5gc in production environments. The attack vector is inferred to be remote via the network interfaces that handle registration messages, as the flaw is triggered by crafted payload data. If exploited, the target service would crash, disrupting 5G core operations until the component is restarted or replaced.