The Open5GS User Plane Function is susceptible to a remote denial of service attack that can be triggered by unauthenticated attackers, potentially disrupting core network operations.

This vulnerability involves a reachable assertion in the lib/pfcp/context.c file. An unauthenticated attacker can trigger a crash in the UPF process by sending a crafted PFCP Session Establishment Request where the address family flags do not align with the configured GTP-U resource.

The exploitation of this vulnerability results in a denial of service, which directly impacts the availability of network services. Given a CVSS score of 7.5, this high-severity flaw could lead to significant service degradation or total loss of connectivity for connected user equipment, necessitating immediate attention to prevent operational disruption.

Immediate Action: Monitor the official Open5GS repository for the release of a patch addressing the assertion failure in lib/pfcp/context.c and apply it as soon as it becomes available.

Proactive Monitoring: Review system logs for frequent crashes or unexpected restarts of the UPF process, as these may indicate an ongoing attempt to exploit this assertion.

Compensating Controls: Restrict network access to the PFCP interface to trusted infrastructure components only, utilizing firewall rules to block unauthorized traffic from reaching the UPF service.

Public Exploit Available: Unknown

Given the potential for remote disruption of critical network infrastructure, administrators must treat this vulnerability as a high priority. While no official patch is currently identified, implementing strict network segmentation around the UPF and monitoring for service instability is essential to mitigate the risk until a vendor update is deployed.