CVE-2025-21040 is a medium-severity vulnerability identified in Samsung Mobile's S Assistant application, specifically affecting versions prior to 9.3.2. The root cause is an improper verification of intent by the ExternalBroadcastReceiver component within the app. Broadcast receivers in Android listen for system-wide or app-specific broadcasts and act upon them. In this case, the ExternalBroadcastReceiver fails to properly validate the incoming intents, which are messages or commands sent between components. This flaw allows a local attacker—someone with physical or local access to the device—to send crafted intents to the S Assistant app. By exploiting this, the attacker can modify itinerary information managed by the assistant. Although the vulnerability does not impact confidentiality directly, it affects the integrity and availability of itinerary data. The CVSS v3.1 score is 5.1 (medium), reflecting that the attack vector is local (AV:L), requires low attack complexity (AC:L), no privileges (PR:N), and no user interaction (UI:N). The scope is unchanged (S:U), with no confidentiality impact (C:N), but partial integrity (I:L) and availability (A:L) impacts. There are no known exploits in the wild currently, and no patches are linked yet, indicating the need for vigilance and prompt updates once available. This vulnerability falls under CWE-925, which concerns improper verification of intent, a common issue in Android apps that can lead to unauthorized actions triggered by malicious intents.

For European organizations, especially those with employees using Samsung mobile devices with S Assistant, this vulnerability poses a risk to the integrity and availability of itinerary and scheduling data. While the confidentiality of data is not compromised, unauthorized modification of itinerary information can disrupt business operations, cause missed meetings or deadlines, and potentially lead to cascading operational inefficiencies. Organizations relying on mobile assistants for scheduling or logistics could see reduced trust in device security and increased risk of social engineering or operational disruption. The local attack vector means that the attacker must have physical or local access to the device, limiting remote exploitation risk but increasing concern in environments with shared or less controlled device access, such as field operations or shared workspaces. The absence of user interaction requirement means the attack can be automated once local access is achieved, increasing the threat in scenarios where devices are left unattended.

European organizations should prioritize updating Samsung S Assistant to version 9.3.2 or later as soon as patches become available. Until then, organizations should enforce strict physical security controls over mobile devices to prevent unauthorized local access. Device management policies should include disabling or restricting the use of broadcast intents from untrusted sources where possible, and monitoring for unusual app behavior or unexpected itinerary changes. Employ Mobile Device Management (MDM) solutions to enforce app updates and restrict installation of unauthorized apps that could facilitate local attacks. Educate users about the risks of leaving devices unattended and the importance of locking devices promptly. Additionally, organizations should audit and limit permissions granted to S Assistant and related apps, reducing the attack surface. Monitoring logs for anomalies related to itinerary modifications can help detect exploitation attempts early.