CVE-2026-30653 is a denial of service vulnerability identified in Free5GC, an open-source 5G core network implementation widely used for research, development, and some production environments. The vulnerability exists in the Authentication Management Function (AMF) component, specifically within the HandleAuthenticationFailure function. When this function processes certain malformed or malicious authentication failure messages, it can cause resource exhaustion or a crash, leading to denial of service. The vulnerability is remotely exploitable without any authentication or user interaction, making it accessible to unauthenticated attackers over the network. The CVSS v3.1 base score of 7.5 reflects the high impact on availability with no impact on confidentiality or integrity. The underlying issue corresponds to CWE-400, which relates to uncontrolled resource consumption. Although no public exploits are currently known, the potential for disruption in 5G core network operations is significant given the critical role of the AMF in managing authentication and mobility. The lack of patches at the time of disclosure necessitates proactive mitigation strategies. This vulnerability highlights the importance of robust input validation and resource management in telecom infrastructure software.

The primary impact of CVE-2026-30653 is the disruption of 5G core network services due to denial of service conditions in the AMF component of Free5GC. This can lead to service outages affecting user authentication and mobility management, potentially causing widespread connectivity issues for subscribers relying on affected networks. Organizations operating 5G infrastructure with Free5GC may experience degraded network availability, impacting customer experience and possibly violating service level agreements. The vulnerability does not compromise data confidentiality or integrity but threatens network reliability and operational continuity. Given the critical nature of 5G networks for communications, emergency services, and IoT applications, such disruptions could have cascading effects on dependent services and industries. The ease of remote exploitation without authentication increases the risk of opportunistic attacks or targeted disruptions by malicious actors.

1. Monitor Free5GC project repositories and security advisories closely for official patches addressing CVE-2026-30653 and apply them promptly once available. 2. Until patches are released, implement network-level protections such as firewall rules or intrusion prevention systems (IPS) to restrict access to the AMF interface from untrusted sources. 3. Employ rate limiting and anomaly detection on authentication failure messages to detect and block suspicious traffic patterns that could trigger the vulnerability. 4. Conduct thorough testing of Free5GC deployments in controlled environments to identify abnormal behavior related to authentication failure handling. 5. Consider deploying redundant AMF instances and failover mechanisms to maintain service availability in case of an attack. 6. Engage with Free5GC community and vendors for guidance and potential workarounds. 7. Incorporate robust logging and monitoring to detect early signs of exploitation attempts. 8. Review and harden overall 5G core network security posture, including segmentation and access controls, to minimize attack surface exposure.