parisneo/lollms-webui is vulnerable to stored Cross-Site Scripting (XSS) that leads to Remote Code Execution (RCE). The vulnerability arises due to inadequate sanitization and validation of model output data, allowing an attacker to inject malicious JavaScript code. This code can be executed within the user's browser context, enabling the attacker to send a request to the `/execute_code` endpoint and establish a reverse shell to the attacker's host. The issue affects various components of the application, including the handling of user input and model output.