The LiteSpeed Cache WordPress plugin before 7.9.2 does not limit one of its HTML optimization routines to stylesheet content, so it can delete the markup that closes an attribute in the rendered page, and combined with unescaped comment author output this allows unauthenticated users whose comments are published to inject event-handler attributes that run JavaScript in the browser of any visitor, including a logged-in administrator, viewing front-end pages while the optimization is enabled.