CVE-2025-34281 is a stored cross-site scripting (XSS) vulnerability identified in ThingsBoard, an open-source IoT platform widely used for device management and data visualization. The flaw exists in versions prior to 4.2.1 within the dashboard's Image Upload Gallery feature. Specifically, the vulnerability arises because the application insufficiently sanitizes SVG files uploaded by users and fails to properly validate the content-type of these files. SVG files can contain embedded JavaScript, and when such a malicious SVG is uploaded and later rendered in the dashboard UI, the embedded script executes in the context of the victim's browser session. This can lead to unauthorized actions such as session hijacking, privilege escalation, or data theft. The vulnerability requires the attacker to have low privileges (authenticated user) and some user interaction (viewing the malicious SVG in the UI). The CVSS 4.0 vector indicates network attack vector, low attack complexity, no privileges required (or low privileges), and user interaction needed, with limited scope and impact confined to confidentiality, integrity, and availability. No known exploits have been reported in the wild, but the risk remains significant given the nature of stored XSS in web applications managing critical IoT infrastructure. The lack of patch links suggests that users should monitor ThingsBoard's official channels for updates or consider upgrading to version 4.2.1 or later where the issue is resolved.

For European organizations, this vulnerability poses a risk primarily to the confidentiality and integrity of data managed through ThingsBoard dashboards. Exploitation could allow attackers to execute arbitrary JavaScript in the context of authenticated users, potentially leading to session hijacking, unauthorized command execution, or manipulation of IoT device data and configurations. Given ThingsBoard's role in industrial IoT and smart infrastructure management, such attacks could disrupt operational technology environments or leak sensitive operational data. The medium CVSS score reflects moderate impact, but the actual risk depends on the deployment context and user privileges. Organizations in sectors like manufacturing, energy, and smart city infrastructure that rely on ThingsBoard could face operational disruptions or data breaches. The requirement for user interaction and low privileges reduces the likelihood of widespread automated exploitation but does not eliminate targeted attacks. Additionally, the stored nature of the XSS means malicious payloads persist and can affect multiple users over time.

European organizations should immediately assess their ThingsBoard deployments to identify versions prior to 4.2.1 and plan upgrades to the latest patched version once available. Until patches are applied, implement strict file upload restrictions by disabling SVG uploads or sanitizing SVG files using specialized libraries that remove embedded scripts and dangerous elements. Employ Content Security Policy (CSP) headers to restrict script execution origins and reduce the impact of potential XSS payloads. Conduct regular security training for users to recognize suspicious dashboard content and avoid interacting with untrusted uploads. Monitor dashboard logs and user activity for unusual behavior indicative of exploitation attempts. Additionally, restrict dashboard access to trusted users and networks, and enforce strong authentication and session management controls to limit the impact of compromised sessions. Consider deploying web application firewalls (WAFs) with custom rules to detect and block malicious SVG uploads or suspicious script execution patterns.