I performed numerous security reviews of WebOS and frankly it was a bit of a problem. I never actually made it to the point of doing kernel exploitation since

I performed numerous security reviews of WebOS and frankly it was a bit of a problem. I never actually made it to the point of doing kernel exploitation since the numerous XSS vuln discoveries kept me pretty busy. What was unfortunate at the time is that the WebOS team didn't seem to take the XSS situation seriously even though XSS on that platform effectively compromised the entire UX. I made at least one POC which emulated WebOS trust dialogs. There's no need to break out of an application sandbox when you can make the application look like WebOS, complete with authentic looking authentication dialogs. I've not looked at it in several years, however. Maybe LuneOS has solved some of the core issues but I'd be skeptical as the whole OS was pretty well designed if your intention was to introduce XSS vulnerabilities.