CVE-2025-21011 is a medium-severity vulnerability classified under CWE-284 (Improper Access Control) affecting Samsung Mobile Devices, specifically the SemSensorService component on Galaxy Watch models prior to the SMR (Security Maintenance Release) August 2025 Release 1. The vulnerability allows a local attacker with limited privileges (low-level privileges) to access sensitive information related to motion and body sensors without requiring user interaction. The vulnerability arises because the SemSensorService does not properly enforce access control policies, enabling unauthorized access to sensor data that could include detailed motion, activity, or biometric information collected by the device. The CVSS 3.1 base score is 5.5, reflecting a medium impact primarily on confidentiality, with no impact on integrity or availability. Exploitation requires local access and some privileges but no user interaction, and the scope is unchanged, meaning the vulnerability affects only the component itself without propagating to other system components. There are no known exploits in the wild at the time of publication, and no patch links have been provided yet, indicating that a fix may be forthcoming or in development. The vulnerability was reserved in November 2024 and published in August 2025, indicating a recent disclosure cycle.

For European organizations, the impact of this vulnerability depends largely on the use of Samsung Galaxy Watch devices within their workforce or customer base. The exposure of sensitive motion and body sensor data could lead to privacy violations, unauthorized profiling, or leakage of biometric data, which is particularly sensitive under GDPR regulations. While the vulnerability does not allow modification or denial of service, the confidentiality breach could undermine trust in wearable devices used for health monitoring, fitness tracking, or employee wellness programs. Organizations in healthcare, insurance, or sectors relying on biometric data could face compliance risks and reputational damage if such data is accessed by unauthorized local actors. Since exploitation requires local access and some privileges, the threat is more relevant in scenarios where devices are shared, lost, or accessed by malicious insiders or attackers who have gained limited device access. The lack of known exploits reduces immediate risk but does not eliminate the potential for targeted attacks, especially in environments with high-value data or sensitive user populations.

European organizations should implement the following specific mitigations: 1) Enforce strict physical security and device access controls to prevent unauthorized local access to Samsung Galaxy Watch devices, including use of strong authentication mechanisms such as PINs or biometric locks. 2) Monitor and restrict installation of untrusted applications or services that could escalate privileges or access sensor data. 3) Educate users about the risks of sharing devices or leaving them unattended. 4) Stay informed about Samsung’s security updates and promptly apply the SMR August 2025 Release 1 or subsequent patches addressing this vulnerability once available. 5) For enterprise deployments, consider mobile device management (MDM) solutions that can enforce security policies on wearable devices and remotely wipe or disable compromised devices. 6) Conduct audits of sensor data access logs if available to detect anomalous access patterns. 7) Evaluate the necessity of sensitive sensor data collection in organizational use cases and limit data exposure where possible.