In Progress® Kendo® UI for jQuery prior to version 2026.3.1015, the Calendar and MultiViewCalendar month content templates render data.url and data.title without proper URL sanitization and HTML attribute encoding. An attacker with low privileges who can control the URL option or culture-derived title values can supply a JavaScript URL or inject event-handler attributes. When a user interacts with an affected calendar, JavaScript can execute in the user's browser context and compromise the confidentiality and integrity of accessible data.