Mozilla Firefox before 3.6 Beta 3 does not properly handle overlong UTF-8 encoding, which makes it easier for remote attackers to bypass cross-site scripting (XSS) protection mechanisms via a crafted string, a different vulnerability than CVE-2010-1210.
https://bugzilla.mozilla.org/show_bug.cgi?id=522634
https://bugzilla.mozilla.org/show_bug.cgi?id=511859
http://hg.mozilla.org/releases/mozilla-1.9.2/rev/e42c563313a0