CVE-2026-30070 in Free5GC
Summary
by MITRE • 08/27/2026
An issue in the HandleGetSharedData function of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) via a crafted input.
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Analysis
by VulDB Data Team • 08/27/2026
The vulnerability identified within the free5GC project, specifically affecting version 4.0.1, resides in the HandleGetSharedData function and represents a significant risk to the availability of 5G core network services. This open-source implementation of the 5G Core Network is widely used for testing and development purposes but has also seen deployment in production-like environments due to its accessibility and feature completeness. The flaw allows an attacker, potentially operating as a malicious user or a compromised network function within the service-based architecture, to trigger a Denial of Service condition by supplying crafted input parameters that exploit improper handling logic within this specific handler.
From a technical perspective, the HandleGetSharedData function is responsible for retrieving shared data contexts from the Unified Data Repository or similar storage mechanisms within the 5G core. The vulnerability likely stems from insufficient validation or error handling when processing inputs related to subscriber profiles, policy settings, or session management data. When an attacker provides malformed or excessively large payloads designed to trigger edge cases in memory allocation, string parsing, or database query execution, the function may fail to handle these anomalies gracefully. This can lead to resource exhaustion, such as CPU spikes due to infinite loops or excessive computation, or memory leaks that eventually cause the application process to crash or become unresponsive. In some implementations of similar functions, this could also manifest as a panic in the underlying Go runtime if nil pointer dereferences are triggered by unexpected data structures resulting from the crafted input.
The operational impact of this vulnerability is severe within the context of 5G network infrastructure. Since free5GC serves as the central nervous system for managing subscriber authentication, mobility management, and session establishment, a Denial of Service attack against its core functions can disrupt service for multiple users simultaneously. If an attacker successfully exploits this flaw to crash or hang the HandleGetSharedData endpoint, it effectively blocks access to critical user data required for network operations. This results in a loss of connectivity for subscribers attempting to register with the network or maintain active sessions. In a broader attack scenario, this vulnerability could be chained with other flaws to facilitate more sophisticated attacks, such as bypassing authentication checks by causing timeouts that force fallback mechanisms, although the primary impact here remains availability disruption.
This issue aligns with CWE-20 Improper Input Validation and potentially CWE-400 Resource Exhaustion if it leads to resource consumption without proper limits. In terms of the MITRE ATT&CK framework for Enterprise or ICS, this behavior is consistent with techniques related to Service Availability attacks, specifically those that target application layer services to degrade performance or cause outages. The lack of robust input sanitization and error handling in high-frequency called functions like HandleGetSharedData highlights a common weakness in rapidly developed open-source projects where security testing may not have covered all edge cases involving malformed data structures.
Mitigation strategies for this vulnerability involve both immediate patching and long-term architectural improvements. Users running free5GC version 4.0.1 should immediately upgrade to the latest stable release where this issue has been addressed by the maintainers through improved input validation and error handling routines in the HandleGetSharedData function. For environments where upgrading is not immediately feasible, network-level mitigations such as rate limiting on API endpoints can help reduce the impact of automated exploitation attempts. Additionally, implementing strict schema validation for all inputs passed to core network functions using standardized JSON schemas or protobuf definitions can prevent malformed data from reaching critical logic paths. Security teams should also monitor logs for unusual patterns in requests to shared data endpoints and consider deploying Web Application Firewalls configured to detect anomalies indicative of this specific DoS vector. Regular security audits focusing on input validation across all service-based interface handlers are recommended to identify similar weaknesses before they can be exploited in production environments.