Previous Topic Title Re-edit Exploit

I discovered this about a couple of hours ago!

I went to this topic:

http://www.bullywiihacks.com/t3764-help-converting-seconds-to-hex-timer-length-modifier

The original URL of the topic was this:

http://www.bullywiihacks.com/t3764-need-help-shitnbitch

I figured I'd just do something stupid and type in the old URL and go to it. I was like "WTF?!" at first, but I figured it was just showing the old title and whatnot. I opened up a new tab and went to the "need help shitnbitch" URL and surely enough, it was actually re-edited!

I wonder if it's a privilege escalation vulnerability that allows ANYONE to edit the title back to the original...

Only admins or moderators can perform this exploit... unless it's a privilege escalation!

These are the permissions for the section:

Yeah, but how the hell was I able to edit the topic title back to the original by using the URL?! It doesn't make any sense.   

???

The one now is much better. Who changed it? I didn't.

I did, but I did it manually (without the URL).