Investigating Security Vulnerabilities in 5G Control and User Planes: Attack Patterns and Protection Strategies

The rollout of 5G Standalone networks introduces unprecedented flexibility and performance through service-based architecture (SBA), virtualization, open APIs, and network slicing, while simultaneously expanding the attack surface across control, user, and cross-plane interfaces. This article provides a systematic, vulnerability-prioritized, selective characterization of the current state of weaknesses specific to the 5G control and user planes and transparent risk scoring. Using a PRISMA-aligned methodology, vulnerabilities are mapped explicitly to 3GPP network functions and interfaces (e.g., AMF, SMF, UPF; N2, N4, SBA APIs) and categorized by operational evidence level ranging from theoretical analysis to documented live-network exploitation. A normalized criticality scoring model integrates likelihood, impact, exploitability, and CVSS-derived severity. The analysis shows that control-plane signaling floods, PFCP misuse, and container escapes stand out as the most pressing risks. It also exposes how little attention has been given to securing the user plane and strengthening slice isolation. The paper wraps up with clear, evidence-based hardening priorities for each plane, along with research areas that matter for today’s 5G networks and the shift toward 6G.