MISP Reflected XSS via Unvalidated Object Type in AnalystData Overmind Thread

Overview

MISP contains a reflected cross-site scripting (XSS) vulnerability in the AnalystDataController::viewForObject action. The method accepted a parent object type parameter from the URL without validation and passed it to the Overmind-themed AnalystData thread view element, where it was interpolated into two translated strings and rendered into the HTML response without output encoding. An authenticated attacker who can induce a victim to navigate to a crafted URL can inject arbitrary JavaScript that executes in the victim's browser within the MISP application context. This may allow the attacker to read session data, manipulate the page, or perform actions on behalf of the victim. 

The vulnerability requires the victim to be authenticated to MISP and to actively visit the attacker-supplied URL. The affected component is the AnalystData controller and the Overmind theme's AnalystData thread element.

Version affected: <2.5.47

Affected

• MISP < 2.5.47

Remediation

The fix introduces two layers of defense. First, the viewForObject action now validates the object_type parameter against the AnalystData::valid_targets whitelist and rejects any value not in that list with a NotFoundException, preventing arbitrary strings from reaching the view layer. Second, the two output sinks in the Overmind thread.ctp template now apply the h() HTML-encoding function to the object type before interpolation into translated strings, ensuring that even if a valid type were to contain special characters, it would be rendered as inert text rather than executable markup.