CVE-2026-93296: MISP Overmind: Stored Cross-Site Scripting via Unescaped Object Names in Statistics Legends
MISP contains a stored cross-site scripting (XSS) vulnerability in the Overmind theme's statistics views. The event General card and the server/feed preview card constructed donut chart legend labels by directly concatenating object name or category keys into an innerHTML string without HTML-encoding. Because MISP object names are user-controllable by any authenticated user with sufficient permissions to create or modify such objects, an attacker could craft a name containing malicious markup. When any other user viewed the affected Overmind dashboard, the injected markup would be interpreted as live HTML/JavaScript in the victim's browser, executing in the context of the MISP application origin. This could allow session hijacking, data exfiltration, or arbitrary actions performed on behalf of the victim.
The vulnerability requires the attacker to have low-level authenticated access to create or rename an object whose name is rendered in the legend, and the victim to view the Overmind event or server preview page. No special browser conditions or race conditions are required.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Wrap the user-controlled label variable (lbl) with escapeHtml() before interpolating it into the innerHTML string in both affected event General card and server/feed preview card view templates.
MISP Overmind statistics views HTML encoding of the user-controlled label variable (lbl) = escapeHtml(lbl)
Event History
Frequently Asked Questions
Can an unauthenticated attacker exploit this issue?
No. Exploitation requires authenticated access with sufficient permission to create or modify an object whose name is rendered in a statistics legend.
What user interaction is required for the payload to execute?
A victim must view an affected Overmind event page or server/feed preview page. The malicious object name is interpreted by the victim's browser when the corresponding donut-chart legend is rendered.
Which users are most exposed?
Users who view Overmind dashboards containing attacker-controlled event, attribute, object-category, server, or feed identifiers are exposed. Code executes in the context of the MISP application origin and can perform actions available to the victim's session.