CVE-2025-21026 is a vulnerability identified in Samsung Mobile Devices affecting the ImsService component prior to the SMR (Security Maintenance Release) September 2025 Release 1. The vulnerability is classified under CWE-280, which pertains to improper handling of insufficient permissions. Specifically, the flaw allows local attackers—those with physical or local access to the device—to interrupt ongoing calls by exploiting the insufficient permission checks within the ImsService. ImsService is responsible for managing IP Multimedia Subsystem (IMS) services, including voice over LTE (VoLTE) and other telephony-related functions. The vulnerability does not require user interaction or elevated privileges, as indicated by the CVSS vector (AV:L/AC:L/PR:N/UI:N), meaning an attacker with local access can exploit it with low complexity and no privileges. The impact is limited to confidentiality, with no direct effect on integrity or availability, and no known exploits are currently reported in the wild. The absence of patch links suggests that remediation may be pending or integrated into upcoming security releases. Given the nature of the vulnerability, it primarily affects the telephony call continuity on Samsung mobile devices, potentially disrupting user experience by allowing call interruptions without proper authorization.

For European organizations, the impact of CVE-2025-21026 is moderate but non-trivial. Many enterprises rely on Samsung mobile devices for communication, including voice calls over IMS networks. An attacker with local access to a device could disrupt calls, potentially affecting critical communications in sectors such as finance, healthcare, and government. Although the vulnerability does not allow data exfiltration or device takeover, call interruptions could lead to operational inefficiencies, missed critical alerts, or degraded trust in mobile communication security. In environments where secure and reliable voice communication is essential, such as emergency services or corporate communications, this vulnerability could be exploited to cause denial of service at the call level. However, since exploitation requires local access and no remote attack vector is present, the overall risk to large-scale operations is limited unless devices are physically compromised.

To mitigate CVE-2025-21026, European organizations should prioritize the following actions: 1) Ensure all Samsung mobile devices are updated with the latest SMR September 2025 Release 1 or subsequent patches once available, as these will address the permission handling flaw in ImsService. 2) Implement strict physical security controls to prevent unauthorized local access to mobile devices, including device lock policies, biometric authentication, and secure storage. 3) Employ Mobile Device Management (MDM) solutions to enforce security policies, monitor device integrity, and remotely lock or wipe devices if lost or stolen. 4) Educate users on the risks of leaving devices unattended and the importance of reporting lost or stolen devices promptly. 5) For high-security environments, consider restricting the use of affected Samsung devices or isolating sensitive communications to devices with verified security patches. 6) Monitor telephony service logs for unusual call interruptions that may indicate exploitation attempts. These targeted measures go beyond generic patching advice by focusing on access control, user awareness, and proactive monitoring tailored to the vulnerability's characteristics.