A critical vulnerability in the Free5GC NSSF component allows unauthenticated attackers to cause a denial of service through malicious API requests.

This vulnerability is a denial of service flaw triggered by sending a crafted POST request to the Nnssf_NSSAIAvailability API, which can be exploited by an unauthenticated remote attacker.

The ability for an unauthenticated attacker to remotely crash the NSSF component poses a significant risk to the availability of the 5G core network. Given the CVSS score of 7.5, this high severity issue could lead to service outages, disrupting critical communication functions and impacting overall network reliability.

Immediate Action: Update the NSSF component to version 1.4.0 or later as specified by the vendor's repository.

Proactive Monitoring: Monitor network traffic for unusual spikes in POST requests directed at the Nnssf_NSSAIAvailability API endpoint.

Compensating Controls: Implement rate limiting and input validation on the NSSF API gateway to drop malformed or excessive requests from unauthorized sources.

Public Exploit Available: Unknown

This vulnerability presents a clear risk to the stability of 5G infrastructure. Administrators should prioritize the update to the fixed version of the NSSF component immediately to eliminate the potential for remote denial of service attacks.