Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. In versions 0.6.34 and below, the functionality that inserts custom prompts into the chat window is vulnerable to DOM XSS when 'Insert Prompt as Rich Text' is enabled, since the prompt body is assigned to the DOM sink .innerHtml without sanitisation. Any user with permissions to create prompts can abuse this to plant a payload that could be triggered by other users if they run the corresponding / command to insert the prompt. This issue is fixed in version 0.6.35.