In Progress® Kendo® UI for jQuery versions starting with 2012.2.710 and prior to 2026.3.1015, the Validator decodes validation messages from data-msg-* attributes and parses the resulting text as HTML. An attacker who can modify a validation message can cause HTML that was correctly escaped in the page attribute to become active markup, including event handlers, when the user triggers validation. Successful exploitation can execute JavaScript in a user's browser and compromise the confidentiality and integrity of data accessible to the affected application. This issue is fixed in version 2026.3.1015.