CVE-2025-40890: Critical XSS Threat in Dashboards – Are Your Users at Risk?

This article details a high-severity stored Cross-Site Scripting (XSS) vulnerability, identified as CVE-2025-40890, affecting dashboard functionalities. This vulnerability allows a low-privilege attacker to inject malicious JavaScript code that can compromise user accounts and application data. Read on to understand the risks and learn how to protect your systems.

CVE-2025-40890 is a stored XSS vulnerability discovered in the dashboard feature of an application. Due to insufficient input validation, a malicious actor with low-level privileges can craft a dashboard containing a JavaScript payload. This malicious dashboard can then be shared with other users, or victims can be socially engineered into importing a specially crafted dashboard template. When a victim views or imports this dashboard, the embedded XSS code executes within their browser session.

The root cause of this vulnerability is the lack of proper input sanitization when handling dashboard configurations. Specifically, parameters that control dashboard elements and their properties are not adequately validated to prevent the injection of arbitrary JavaScript code. An attacker can inject JavaScript code within the dashboard configuration (e.g., within a chart title, description, or even data source parameters).

The injected script then executes when a user views the affected dashboard. Because the script executes in the user’s browser context within the application’s origin, it can access cookies, session tokens, and other sensitive information.

The Common Vulnerability Scoring System (CVSS) assigns this vulnerability a score of 7.9 (HIGH). This score reflects the potential impact and ease of exploitation. The breakdown of the CVSS vector likely includes:

• Attack Vector (AV): Network (N)
• Attack Complexity (AC): Low (L)
• Privileges Required (PR): Low (L)
• User Interaction (UI): Required (R)
• Scope (S): Changed (C)
• Confidentiality Impact (C): Low (L)
• Integrity Impact (I): High (H)
• Availability Impact (A): Low (L)

Successful exploitation of CVE-2025-40890 can lead to various malicious outcomes, including:

• Account Takeover: The attacker can steal user session cookies and gain unauthorized access to their accounts.
• Data Modification: The attacker can modify application data, potentially leading to data corruption or financial loss.
• Application Defacement: The attacker can alter the appearance of the application, causing reputational damage.
• Malware Distribution: The attacker can redirect users to malicious websites or trick them into downloading malware.
• Denial of Service: The attacker can disrupt application availability by injecting code that causes errors or crashes.
• Sensitive Information Disclosure: Access to limited sensitive information accessible to the compromised user.

To mitigate the risk of CVE-2025-40890, the following steps should be taken:

• Apply the Patch: Immediately apply the security patch or update provided by the vendor. This is the most effective way to address the vulnerability.
• Input Validation: Implement robust input validation and sanitization for all dashboard parameters, especially those related to titles, descriptions, and data sources. Use contextual output encoding to escape special characters before rendering data in the browser.
• Content Security Policy (CSP): Implement a strict Content Security Policy (CSP) to restrict the sources from which the browser is allowed to load resources. This can help prevent the execution of injected JavaScript code.
• Regular Security Audits: Conduct regular security audits and penetration testing to identify and address potential vulnerabilities.
• User Education: Educate users about the risks of social engineering and the importance of not importing dashboards from untrusted sources.
• Least Privilege Principle: Enforce the principle of least privilege, granting users only the necessary permissions to perform their tasks. This can limit the impact of a successful XSS attack.

• Nozomi Networks Advisory: https://security.nozominetworks.com/NN-2025:11-01
• CVE Details: (When available, insert the official CVE details page link here. As it’s a future CVE, this will be available after the CVE is entered into the NVD.)