Validate-before-filter vulnerability in cleanhtml.pl 1.129 in LiveJournal CVS before Dec 7 2005, when the cleancss option is enabled, allows remote attackers to conduct cross-site scripting (XSS) attacks via a "\" (backslash) within a "javascript" scheme in a style property (such as "javas\cript"), which bypasses the "javascript" check before the "\" is stripped and then rendered in web browsers that allow scripting in style sheets.
https://exchange.xforce.ibmcloud.com/vulnerabilities/23839
http://secunia.com/advisories/18157
http://marc.info/?l=full-disclosure&m=113504421421972&w=2
http://cvs.livejournal.org/browse.cgi/livejournal/cgi-bin/cleanhtml.pl
http://archives.neohapsis.com/archives/fulldisclosure/2005-12/1000.html