CVE-2025-4394 Overview
CVE-2025-4394 affects the Medtronic MyCareLink Patient Monitor, a home-based device used to transmit data from implanted cardiac devices to clinicians. The monitor stores data on an unencrypted internal filesystem. An attacker with physical access to the device can read and modify files on that storage. The weakness is classified as cleartext storage of sensitive information [CWE-312]. Medtronic addressed the issue through updates released on June 25, 2025, for MyCareLink Patient Monitor models 24950 and 24952.
Critical Impact
Physical access to a MyCareLink Patient Monitor allows an attacker to extract patient data, tamper with stored files, and potentially undermine the integrity of transmitted cardiac telemetry.
Affected Products
- Medtronic MyCareLink Patient Monitor model 24950 (before June 25, 2025)
- Medtronic MyCareLink Patient Monitor model 24952 (before June 25, 2025)
- Implanted cardiac device ecosystems relying on these monitors for remote transmissions
Discovery Timeline
- 2025-07-24 - CVE-2025-4394 published to the National Vulnerability Database
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-4394
Vulnerability Analysis
The MyCareLink Patient Monitor stores operational data, configuration, and patient information on internal storage without encryption. An attacker who obtains physical possession of the device can mount or extract the storage medium and access its contents in cleartext. The same access path allows the attacker to modify files, which can influence device behavior on next boot or during subsequent transmissions to the clinician network.
The monitor operates as a bridge between an implanted cardiac device and the Medtronic CareLink network. Cleartext storage on this bridge exposes sensitive patient telemetry and configuration state. It also weakens trust in the data forwarded to healthcare providers.
Root Cause
The root cause is missing full-disk or file-level encryption on the monitor's internal filesystem. The device relies on the physical enclosure as the sole protection boundary. When that boundary is defeated, no cryptographic control prevents disclosure or tampering. This is a design-level control failure aligned with [CWE-312: Cleartext Storage of Sensitive Information].
Attack Vector
Exploitation requires physical access to the monitor. Patient monitors deployed in homes, clinics, or in transit are the realistic exposure surface. An attacker can disassemble the device, attach to internal storage, and read or write filesystem contents directly. No network access, credentials, or user interaction are required once the device is in the attacker's hands.
The vulnerability does not describe a documented code-level primitive. See the CISA ICS Medical Advisory and the Medtronic Security Bulletin for vendor detail.
Detection Methods for CVE-2025-4394
Indicators of Compromise
- Physical signs of tampering on the monitor enclosure, screws, or seals
- Missing, replaced, or unexpectedly returned patient monitors
- Inconsistent or unexpected transmission data patterns from a specific monitor serial number
Detection Strategies
- Track device inventory and serial numbers for all deployed MyCareLink Patient Monitors and reconcile against clinician records
- Monitor CareLink backend logs for anomalous transmission content, timing, or duplicate submissions tied to a single device
- Correlate patient-reported incidents of lost or stolen monitors with subsequent transmission activity from the affected serial number
Monitoring Recommendations
- Establish a return-to-service inspection workflow for any monitor recovered from an uncontrolled environment
- Review Medtronic advisory bulletins on a recurring cadence for firmware and configuration updates
- Maintain audit trails for physical custody of loaner or replacement monitors
How to Mitigate CVE-2025-4394
Immediate Actions Required
- Confirm all deployed MyCareLink Patient Monitor models 24950 and 24952 have received the updates issued on or after June 25, 2025
- Instruct patients to store the monitor in a secure location and report loss, theft, or tampering immediately
- Quarantine any monitor suspected of physical compromise and coordinate replacement through Medtronic
Patch Information
Medtronic released updates for MyCareLink Patient Monitor models 24950 and 24952 that address CVE-2025-4394 as of June 25, 2025. Refer to the Medtronic Security Bulletin and the CISA ICS Medical Advisory ICSMA-25-205-01 for update distribution details and clinician guidance.
Workarounds
- Enforce physical security controls for monitors in clinical settings, including locked storage and chain-of-custody logging
- Educate patients on secure home placement of the monitor and prompt reporting of unauthorized access
- Decommission and securely dispose of retired monitors following Medtronic guidance to prevent residual data disclosure
# Configuration example
# No device-side configuration mitigates unencrypted storage.
# Coordinate with Medtronic to apply the vendor update for models 24950 and 24952
# released on 2025-06-25 and follow ICSMA-25-205-01 handling guidance.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
