CVE-2022-38249

What it actually does

Allows unauthenticated remote attackers to inject arbitrary JavaScript into the MTR component that executes in other users' browsers under the application's origin, enabling theft of session tokens or credentials and limited UI manipulation.

Why it matters to the business

Attackers can hijack administrative sessions in the monitoring platform, potentially altering alert configurations, exfiltrating sensitive infrastructure data, or using the system as a pivot point; the vulnerability has existed for over four years with no listed fixed version, increasing long-term exposure risk across deployments.

How an attack unfolds

An attacker identifies the MTR component endpoint, crafts a request containing a malicious script payload that is not sanitized, and tricks an authenticated user into triggering the page; the script then runs in the victim's browser context to capture cookies or perform actions on their behalf.

How to fix it

Upgrade Nagios XI to the latest available version that resolves the MTR component XSS issue; apply web application firewall rules to block common XSS patterns; enforce strict input validation and output encoding on all MTR-related parameters; monitor vendor advisories for any subsequent patches.

How to confirm the fix worked

Review release notes and changelogs for MTR component updates after version 1.0.4; test the component with known XSS test payloads in a non-production environment and confirm that scripts are neutralized; scan the application with an automated web vulnerability scanner configured for reflected and stored XSS.

Typical attack path

1. Locate the exposed Nagios XI MTR component URL
2. Craft and deliver a URL or form input containing a script tag or event handler
3. Induce a victim user (via phishing or shared link) to load the malicious input
4. Execute the injected script to steal session data or perform unauthorized actions within the application

How to detect it

Inspect web server and application logs for requests to the MTR endpoint containing HTML tags, JavaScript keywords, or encoded script payloads; look for anomalous responses that include user-supplied script content; correlate successful XSS attempts with subsequent unusual administrative actions or session token usage from unexpected locations.

• <script
• onerror=
• javascript:
• alert(
• MTR component requests with encoded angle brackets

What your security team should do

• Prioritize upgrade of Nagios XI instances running version 5.8.6 or earlier to a patched release as soon as one is published
• Implement compensating controls such as Content-Security-Policy headers and input sanitization immediately
• Review access logs for MTR component requests containing script tags or suspicious encoding
• Educate administrators on recognizing phishing attempts that target monitoring dashboards