A critical buffer overflow vulnerability in the OpenAirInterface CN5G AMF component allows unauthenticated remote attackers to crash systems or potentially execute arbitrary code.

The vulnerability is a buffer overflow occurring within the NAS message processing logic. An unauthenticated attacker can trigger this flaw by sending a malformed IMSI string exceeding 1000 characters to the N1 port.

The ability for an unauthenticated attacker to execute code or cause a denial of service on a Core Network 5G (CN5G) Access and Mobility Management Function (AMF) presents a severe risk to telecommunications infrastructure. Given the CVSS score of 7.5, this vulnerability represents a significant threat to service availability and network integrity, potentially leading to widespread outages or unauthorized system access.

Immediate Action: Restrict access to the N1 interface to trusted network segments only and monitor vendor channels for the release of a security patch that addresses the buffer overflow.

Proactive Monitoring: Monitor system logs for abnormal traffic patterns on the N1 interface, specifically looking for unusually long IMSI strings or unexpected service restarts of the AMF process.

Compensating Controls: Implement rate limiting and input validation at the network perimeter or via a firewall to block malformed NAS messages before they reach the AMF.

Public Exploit Available: Yes — a published proof of concept exists, attributed to the security researcher's write-up referenced in the CVE record.

The risk posed by this vulnerability is significant due to the critical role of the AMF in 5G network operations. Organizations should prioritize restricting exposure of the N1 port and maintain heightened vigilance for unauthorized attempts to interact with the AMF until a formal vendor patch is verified and deployed.