The mb_strcut function in Libmbfl 1.1.0, as used in PHP 5.3.x through 5.3.3, allows context-dependent attackers to obtain potentially sensitive information via a large value of the third parameter (aka the length parameter).
http://www.vupen.com/english/advisories/2011/0077
http://www.vupen.com/english/advisories/2011/0021
http://www.vupen.com/english/advisories/2011/0020
http://www.ubuntu.com/usn/USN-1042-1
http://www.redhat.com/support/errata/RHSA-2011-0196.html
http://www.php.net/ChangeLog-5.php
http://www.mandriva.com/security/advisories?name=MDVSA-2010:225
http://secunia.com/advisories/43189
http://secunia.com/advisories/42812
http://secunia.com/advisories/42135
http://marc.info/?l=bugtraq&m=130331363227777&w=2
http://lists.fedoraproject.org/pipermail/package-announce/2011-January/052845.html
http://lists.fedoraproject.org/pipermail/package-announce/2011-January/052836.html