CVE-2026-94372: Stored Cross-Site Scripting via Unescaped Galaxy Cluster Tag Names in MISP Default Theme Galaxies Index
MISP contains a stored cross-site scripting (XSS) vulnerability in the default theme's Galaxies index page. When a MISP instance detects unknown custom or default galaxy clusters during synchronization, it renders sample tag names in an informational notice directed at site administrators. In the default theme, these sample tag names were inserted into the HTML output without HTML-entity encoding. A user with tag-editor privileges could craft a malicious misp-galaxy tag containing arbitrary script. When a site administrator subsequently viewed the Galaxies index page, the crafted tag content was interpreted as executable markup in the administrator's browser session, enabling the attacker to read session data, perform actions on behalf of the administrator, or otherwise compromise the administrator's browser context. The Overmind theme already applied HTML escaping to the same values and was not affected. The vulnerability requires the attacker to possess tag-editor-level access to create the crafted tag and requires the victim (a site administrator) to view the Galaxies index page in the default theme. The impact is limited to the administrator's browser session and does not directly compromise the MISP server process.
Version affected: <2.5.47
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
MISPto a version that resolves this vulnerability.Fixed in 2.5.47 - Configuration
In the default theme’s Galaxies index informational notice, HTML-encode each sample tag name using CakePHP’s h() before inserting it into the HTML output, so that characters like angle brackets, quotes, and ampersands are rendered as inert entities.
MISP default theme (Galaxies index page) Apply CakePHP h() HTML-encoding to sample galaxy cluster tag names before HTML interpolation = CakePHP h()
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Only MISP deployments using the default theme are affected. The Overmind theme escapes the relevant tag values and is not affected.
What access and user interaction are required for exploitation?
An attacker needs tag-editor privileges to create a malicious misp-galaxy tag. A site administrator must then visit the Galaxies index page while using the default theme.
What is the practical impact if exploitation succeeds?
The malicious tag can execute markup in the site administrator's browser context. This can allow actions using the administrator's session or access to session data, but the described impact is limited to that browser session.
What can be done if the fix cannot be applied immediately?
Use the Overmind theme rather than the default theme, since Overmind HTML-escapes the affected values. Restrict tag-editor privileges to trusted users and avoid having administrators visit the Galaxies index page when untrusted custom galaxy tags may be present.