The strip_tags function in PHP 4.x up to 4.3.7, and 5.x up to 5.0.0RC3, does not filter null (\0) characters within tag names when restricting input to allowed tags, which allows dangerous tags to be processed by web browsers such as Internet Explorer and Safari, which ignore null characters and facilitate the exploitation of cross-site scripting (XSS) vulnerabilities.

Buffer overflow in the imap_fetch_overview function in the IMAP functionality (php_imap.c) in PHP before 4.3.3 allows remote attackers to cause a denial of service (segmentation fault) and possibly execute arbitrary code via a long e-mail address in a (1) To or (2) From header.

Buffer overflows in PHP before 4.3.3 have unknown impact and unknown attack vectors.

The php_check_safe_mode_include_dir function in fopen_wrappers.c of PHP 4.3.x returns a success value (0) when the safe_mode_include_dir variable is not specified in configuration, which differs from the previous failure value and may allow remote attackers to exploit file include vulnerabilities in PHP applications.

Integer overflows in (1) base64_encode and (2) the GD library for PHP before 4.3.3 have unknown impact and unknown attack vectors.

Integer signedness error in emalloc() function for PHP before 4.3.2 allow remote attackers to cause a denial of service (memory consumption) and possibly execute arbitrary code via negative arguments to functions such as (1) socket_recv, (2) socket_recvfrom, and possibly other functions.

Buffer overflow in openlog function for PHP 4.3.1 on Windows operating system, and possibly other OSes, allows remote attackers to cause a crash and possibly execute arbitrary code via a long filename argument.