CVE-2025-4393 is a vulnerability identified in Medtronic's MyCareLink Patient Monitor models 24950 and 24952, specifically affecting versions released before June 25, 2025. The vulnerability arises from improper handling of deserialization of untrusted data within an internal service of the device. Deserialization is the process of converting binary or serialized data back into an object or data structure. When untrusted data is deserialized without proper validation or sanitization, it can lead to severe security issues such as remote code execution, privilege escalation, or denial of service. In this case, a local attacker with access to the device can craft a malicious binary payload that, when processed by the vulnerable deserialization service, can cause the service to crash or allow the attacker to elevate their privileges on the device. The CVSS v3.1 base score is 6.5, indicating a medium severity level. The vector string (AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:H) shows that the attack requires local access (AV:L), high attack complexity (AC:H), low privileges (PR:L), no user interaction (UI:N), unchanged scope (S:U), low confidentiality impact (C:L), high integrity impact (I:H), and high availability impact (A:H). This means that while the attacker needs local access and some skill, the consequences can be significant, including potential compromise of data integrity and availability of the patient monitoring device. No known exploits are currently reported in the wild, and no patches are listed yet, indicating that mitigation may rely on vendor updates or operational controls. The vulnerability is categorized under CWE-502, which is a common weakness related to unsafe deserialization practices.

For European healthcare organizations, this vulnerability poses a significant risk due to the critical nature of patient monitoring devices. Exploitation could lead to device malfunction or unauthorized privilege escalation, potentially disrupting patient monitoring and care. This could result in delayed or incorrect medical responses, risking patient safety and violating healthcare regulations such as GDPR and the EU Medical Device Regulation (MDR). Additionally, compromised devices could be leveraged as entry points for broader network intrusions within hospital environments, threatening confidentiality and integrity of sensitive patient data. The requirement for local access somewhat limits remote exploitation, but insider threats or attackers gaining physical or network-level access to these devices remain a concern. The high integrity and availability impacts mean that successful exploitation could alter device behavior or cause denial of service, both unacceptable in medical contexts. The medium CVSS score reflects the balance between exploitation difficulty and potential damage, but the criticality of the affected systems elevates the practical risk level for healthcare providers.

1. Immediate operational mitigation should include restricting physical and network access to MyCareLink Patient Monitor devices to trusted personnel only, implementing strict access controls and monitoring. 2. Network segmentation should isolate these devices from general hospital networks to minimize attack surface and lateral movement opportunities. 3. Regular auditing and logging of device interactions can help detect anomalous activities indicative of exploitation attempts. 4. Coordinate with Medtronic for timely receipt and deployment of security patches or firmware updates addressing this vulnerability once available. 5. Employ application whitelisting and endpoint protection solutions on connected systems to detect and prevent execution of unauthorized payloads. 6. Conduct staff training to raise awareness about the risks of local device tampering and the importance of physical security. 7. Review and update incident response plans to include scenarios involving medical device compromise. 8. Consider deploying intrusion detection systems tailored for medical device environments to identify suspicious deserialization activities. These measures go beyond generic advice by focusing on operational controls, network architecture, and vendor coordination specific to the healthcare context and the nature of this vulnerability.