CVE-2011-4957
The make_clickable function in wp-includes/formatting.php in WordPress before 3.1.1 does not properly check URLs before passing them to the PCRE library, which allows remote attackers to cause a denial of service (crash) via a comment with a crafted URL that triggers many recursive calls.
Date published : 2012-06-27
http://core.trac.wordpress.org/ticket/16892