Integer overflow in the xml_utf8_decode function in ext/xml/xml.c in PHP before 5.2.11 makes it easier for remote attackers to bypass cross-site scripting (XSS) and SQL injection protection mechanisms via a crafted string that uses overlong UTF-8 encoding, a different vulnerability than CVE-2010-3870.

The utf8_decode function in PHP before 5.3.4 does not properly handle non-shortest form UTF-8 encoding and ill-formed subsequences in UTF-8 data, which makes it easier for remote attackers to bypass cross-site scripting (XSS) and SQL injection protection mechanisms via a crafted string.