The last time I tried this, the browser had a notification that it was out of date and needed updates.
Thinking about this broke my brain a little. I have no idea how to apply software updates to the virtual browser on the virtual tablet running in a virtual room simulated by my (hopefully real) PC.
There have been many exploits throughout the years, including this particular exploit with bytecode, though in LuaJIT. Some were source engine related, some LuaJIT related, some web browser related (Awesomium) and some even steam overlay related.
I believe one funny thing about Awesomium was being able to read arbitrary files outside of the sandboxed virtual file system by using the file:// uri scheme. I think some debug related commands in source engine would also allow you to get a list of files outside of the virtual file system.
At one point someone even managed to install actual malware on my computer and sent me screenshots of my desktop. I forgot what the exploit was though.
Damn. That's the scariest thing I've read all week.
This thread is really making me consider buying another computer for all gaming related things...
A game called Mordhau (based on Unreal engine) had a built-in "message of the day" feature where server owners can put in a URL that loads an in-game browser when the player connects. No client side option existed to disable the browser and I believe the devs eventually disabled it completely but I'm not sure the status of it now.
Just shows how complex games / game engines are getting where you have an embedded web browser for seemingly no good reason.