Buffer overflow in PHP before 5.2.0 allows remote attackers to execute arbitrary code via crafted UTF-8 inputs to the (1) htmlentities or (2) htmlspecialchars functions.

Integer overflow in PHP 5 up to 5.1.6 and 4 before 4.3.0 allows remote attackers to execute arbitrary code via an argument to the unserialize PHP function with a large value for the number of array elements, which triggers the overflow in the Zend Engine ecalloc function (Zend/zend_alloc.c).

Race condition in the symlink function in PHP 5.1.6 and earlier allows local users to bypass the open_basedir restriction by using a combination of symlink, mkdir, and unlink functions to change the file path after the open_basedir check and before the file is opened by the underlying system, as demonstrated by symlinking a symlink into a subdirectory, to point to a parent directory via .. (dot dot) sequences, and then unlinking the resulting symlink.

PHP 4.x up to 4.4.4 and PHP 5 up to 5.1.6 allows local users to bypass certain Apache HTTP Server httpd.conf options, such as safe_mode and open_basedir, via the ini_restore function, which resets the values to their php.ini (Master Value) defaults.

The error_log function in basic_functions.c in PHP before 4.4.4 and 5.x before 5.1.5 allows local users to bypass safe mode and open_basedir restrictions via a "php://" or other scheme in the third argument, which disables safe mode.

The c-client library 2000, 2001, or 2004 for PHP before 4.4.4 and 5.x before 5.1.5 do not check the (1) safe_mode or (2) open_basedir functions, and when used in applications that accept user-controlled input for the mailbox argument to the imap_open function, allow remote attackers to obtain access to an IMAP stream data structure and conduct unauthorized IMAP actions.