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

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.

php.exe in PHP 3.0 through 4.2.2, when running on Apache, does not terminate properly, which allows remote attackers to cause a denial of service via a direct request without arguments.

The imap_header function in the IMAP functionality for PHP before 4.3.0 allows remote attackers to cause a denial of service via an e-mail message with a large number of "To" addresses, which triggers an error in the rfc822_write_address function.

The mail function in PHP 4.x to 4.2.2 does not filter ASCII control characters from its arguments, which could allow remote attackers to modify mail message content, including mail headers, and possibly use PHP as a "spam proxy."

move_uploaded_file in PHP does not does not check for the base directory (open_basedir), which could allow remote attackers to upload files to unintended locations on the system.