Overview
CVE-2025-3261 details a stored Cross-Site Scripting (XSS) vulnerability found in ThingsBoard, an open-source IoT platform. Specifically, versions prior to v4.2.1 are susceptible. This flaw allows an authenticated user to upload malicious SVG images through the “Image Gallery” feature. When these images are accessed, they can execute arbitrary JavaScript code within a user’s browser session.
Technical Details
The vulnerability stems from insufficient input validation within the ImageController. When an SVG image is uploaded, the system fails to properly sanitize the file for potentially malicious JavaScript code embedded within the SVG markup. This allows an attacker to inject JavaScript that executes when:
- Any user accesses the public API endpoint serving the malicious SVG image.
- The malicious SVG image is embedded within an
iframeelement, such as during widget creation, and subsequently deployed to any page (e.g., dashboards).
The injected JavaScript code then executes in the context of the user accessing the affected page or API endpoint.
CVSS Analysis
At the time of publication, the CVSS score for CVE-2025-3261 is not yet available (N/A). However, given the nature of stored XSS vulnerabilities, it is expected to receive a medium to high severity rating depending on the scope of access and potential impact. We will update this section as soon as the official CVSS score is released.
Possible Impact
A successful exploit of this vulnerability can have significant consequences:
- Account Compromise: An attacker can execute malicious code in the context of other users’ sessions, potentially stealing their session cookies or credentials, leading to account takeover.
- Data Theft: Access to sensitive data within the ThingsBoard platform could be compromised.
- Unauthorized Actions: The attacker could perform unauthorized actions on behalf of the victim, such as modifying dashboards, creating new users, or altering device configurations.
- Phishing Attacks: The injected script could be used to redirect users to phishing websites or display fake login prompts to steal credentials.
Mitigation and Patch Steps
The recommended mitigation is to upgrade your ThingsBoard instance to version 4.2.1 or later. This version includes a fix that properly sanitizes uploaded SVG images, preventing the execution of malicious JavaScript code. Here’s how to update:
- Backup Your Data: Before performing any upgrade, always back up your ThingsBoard database and configuration files.
- Follow the Official Upgrade Guide: Refer to the official ThingsBoard documentation for detailed upgrade instructions specific to your deployment environment (e.g., Docker, Kubernetes, bare-metal).
- Verify the Upgrade: After the upgrade, verify that the XSS vulnerability is no longer present by attempting to upload a known malicious SVG image and confirming that the injected code does not execute.
References
Checkmarx Advisory: CVE-2025-3261
ThingsBoard Commit: Fix for SVG XSS Vulnerability
