CVE-2025-40890: Dashboard Stored XSS Vulnerability

CVE-2025-40890 Overview

CVE-2025-40890 is a stored Cross-Site Scripting (XSS) vulnerability [CWE-79] affecting the Dashboards functionality of a Nozomi Networks product. The flaw stems from improper validation of an input parameter when dashboards are created, shared, or imported. An authenticated low-privilege user can craft a malicious dashboard containing a JavaScript payload and share it with other users, or socially engineer a victim into importing a malicious dashboard template. When the victim views or imports the dashboard, the payload executes in the victim's browser context.

Critical Impact
Successful exploitation allows an attacker to perform unauthorized actions as the victim, including modifying application data, disrupting application availability, and accessing limited sensitive information.

Affected Products

Nozomi Networks product with Dashboards functionality (see vendor advisory for specific versions)
Not Available
Not Available

Discovery Timeline

2025-11-25 - CVE-2025-40890 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-40890

Vulnerability Analysis

The vulnerability is a stored XSS issue classified under [CWE-79]. The Dashboards feature accepts user-supplied input without sufficient validation or output encoding. An attacker with authenticated low-privilege access can embed JavaScript into a dashboard object. The malicious payload persists server-side and executes when another user renders or imports the dashboard.

Exploitation requires authentication and a victim interaction such as opening a shared dashboard or importing a template file. The browser-context execution inherits the victim's session, allowing the attacker to invoke privileged API operations available to that user. According to the vendor advisory, impact extends beyond confidentiality to integrity and availability of the application.

Root Cause

The root cause is improper neutralization of input during web page generation. A dashboard input parameter is not validated or encoded before being rendered in the application UI. JavaScript embedded in this parameter is therefore stored and later executed as part of the dashboard view.

Attack Vector

The attack vector is network-based but requires both authentication (low privileges) and user interaction. Two practical paths exist. First, an attacker shares a malicious dashboard with internal users through the application's sharing features. Second, the attacker distributes a dashboard template file and convinces a victim to import it. In both paths, the payload triggers in the victim's authenticated browser session.

No verified public exploit code is available. Refer to the Nozomi Networks Security Advisory for technical details.

Detection Methods for CVE-2025-40890

Indicators of Compromise

Dashboard objects containing <script> tags, JavaScript event handlers (e.g., onerror, onload), or javascript: URIs in stored fields.
Unexpected outbound HTTP requests from user browsers immediately after rendering a dashboard view.
Unusual API calls performed under a victim's session shortly after they opened or imported a shared dashboard.
Imported dashboard template files (.json or equivalent) received from unverified or external sources.

Detection Strategies

Inspect dashboard storage and template imports for HTML or JavaScript syntax in fields intended to hold plain text or structured data.
Correlate dashboard share or import events with subsequent privileged actions performed by the recipient account.
Monitor browser-side Content Security Policy (CSP) violation reports if CSP is enforced on the application.
Review web server logs for repeated requests to dashboard endpoints submitting payloads that include script delimiters or encoded variants.

Monitoring Recommendations

Enable detailed audit logging for dashboard creation, modification, sharing, and import events.
Forward application and proxy logs to a centralized analytics platform to correlate user actions with session anomalies.
Alert on low-privilege accounts creating dashboards that are subsequently shared with administrators or service accounts.
Track session token reuse patterns that may indicate session-riding via injected scripts.

How to Mitigate CVE-2025-40890

Immediate Actions Required

Apply the fixed version published in the Nozomi Networks Security Advisory NN-2025:11-01.
Restrict dashboard sharing and import capabilities to trusted users until the patch is deployed.
Audit existing dashboards and dashboard templates for embedded scripts or suspicious payloads.
Reset sessions for any users who imported or viewed untrusted dashboards during the exposure window.

Patch Information

Consult the Nozomi Networks Security Advisory for the specific fixed versions and upgrade procedures. The vendor advisory is the authoritative source for patch availability and affected version ranges.

Workarounds

Do not import dashboard templates from untrusted or unverified sources.
Limit dashboard creation and sharing permissions to administrators where feasible.
Enforce a strict Content Security Policy on the application to reduce the impact of inline script execution.
Educate users to treat shared dashboards from low-privilege or external accounts as untrusted content.

bash

# Configuration example
# Refer to the vendor advisory for exact configuration guidance:
# https://security.nozominetworks.com/NN-2025:11-01