hacked? cache poisoning?

i checked https://www.rlslog.net today and there is an extra iframe with banner at the very end of the page which is not supposed to be there. i checked the themes and there is no code which could be reponsible for that banner.

when i view the source code of the iframe, it says this in the title of the page:

Source code: wyciwyg://1/https://www.rlslog.net

this is obviously not a standard situation, it should say just

Source code: https://www.rlslog.net

i googled “wyciwyg” a bit and it looks like old firefox bug related to cache poisoning. i have no idea what that really means and how could someone exploit it when it’s years old bug. i scanned my pc with spybot and there is no infection. i cleared firefox cache and the problem remains there. i tried in different browser and the iframe with banners shows up as well. theme files werent changed in last few days either.

some quick help would help me a lot. is this possibly a new exploit??