In Progress® Kendo® UI for jQuery, in v2026.3.811 and earlier, the Scheduler Day, Timeline, Month, and Agenda views insert resource color values into quoted event wrapper attributes without proper encoding. An attacker who can control a resource color can inject additional HTML attributes, including event handlers, and execute JavaScript in a user's browser when the affected event is interacted with. Successful exploitation can compromise the confidentiality and integrity of data accessible to the affected application. The earliest affected version has not been confirmed. This issue is fixed in version 2026.3.1015.