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.

intl/uconv/util/nsUnicodeDecodeHelper.cpp in Mozilla Firefox before 3.6.7 and Thunderbird before 3.1.1 inserts a U+FFFD sequence into text in certain circumstances involving undefined positions, which might make it easier for remote attackers to conduct cross-site scripting (XSS) attacks via crafted 8-bit text.

Mozilla Firefox before 3.6.7 and Thunderbird before 3.1.1 do not properly implement read restrictions for CANVAS elements, which allows remote attackers to obtain sensitive cross-origin information via vectors involving reference retention and node deletion.

Buffer overflow in pngpread.c in libpng before 1.2.44 and 1.4.x before 1.4.3, as used in progressive applications, might allow remote attackers to execute arbitrary code via a PNG image that triggers an additional data row.

The nsIScriptableUnescapeHTML.parseFragment method in the ParanoidFragmentSink protection mechanism in Mozilla Firefox before 3.5.17 and 3.6.x before 3.6.14, Thunderbird before 3.1.8, and SeaMonkey before 2.0.12 does not properly sanitize HTML in a chrome document, which makes it easier for remote attackers to execute arbitrary JavaScript with chrome privileges via a javascript: URI in input to an extension, as demonstrated by a javascript:alert sequence in (1) the HREF attribute of an A element or (2) the ACTION attribute of a FORM element.