Security vendor F-Secure was defaced a few days ago by a turkish defacement crew.
"So how did this happen? The server itself is quite well hardened, but
the web forum software had an unannounced security patch silently
released by the vendor nine days ago. The defacement gang learned of
the vulnerability and went through the net searching for vulnerable
forums and changed the front page of such forums to their "greeting".
"
Forum Link: http://www.f-secure.com/weblog/archives/00001336.html