Multiple integer signedness errors in the printf function family in PHP 4 before 4.4.5 and PHP 5 before 5.2.1 on 64 bit machines allow context-dependent attackers to execute arbitrary code via (1) certain negative argument numbers that arise in the php_formatted_print function because of 64 to 32 bit truncation, and bypass a check for the maximum allowable value; and (2) a width and precision of -1, which make it possible for the php_sprintf_appendstring function to place an internal buffer at an arbitrary memory location.