PHP — популярный язык сценариев общего назначения, особенно подходящий для веб-разработки.

PHP 4 before 4.4.5, and PHP 5 before 5.2.1, when register_globals is enabled, allows context-dependent attackers to execute arbitrary code via deserialization of session data, which overwrites arbitrary global variables, as demonstrated by calling session_decode on a string beginning with "_SESSION|s:39:".

The session extension in PHP 4 before 4.4.5, and PHP 5 before 5.2.1, calculates the reference count for the session variables without considering the internal pointer from the session globals, which allows context-dependent attackers to execute arbitrary code via a crafted string in the session_register after unsetting HTTP_SESSION_VARS and _SESSION, which destroys the session data Hashtable.

PHP 5.2.1 allows context-dependent attackers to read portions of heap memory by executing certain scripts with a serialized data input string beginning with S:, which does not properly track the number of input bytes being processed.

Buffer underflow in the header function in PHP 5.2.0 allows context-dependent attackers to execute arbitrary code by passing an all-whitespace string to this function, which causes it to write '\0' characters in whitespace that precedes the string.

The resource system in PHP 5.0.0 through 5.2.1 allows context-dependent attackers to execute arbitrary code by interrupting the hash_update_file function via a userspace (1) error or (2) stream handler, which can then be used to destroy and modify internal resources. NOTE: it was later reported that PHP 5.2 through 5.2.13 and 5.3 through 5.3.2 are also affected.

The mb_parse_str function in PHP 4.0.0 through 4.4.6 and 5.0.0 through 5.2.1 sets the internal register_globals flag and does not disable it in certain cases when a script terminates, which allows remote attackers to invoke available PHP scripts with register_globals functionality that is not detectable by these scripts, as demonstrated by forcing a memory_limit violation.

The resource system in PHP 4.0.0 through 4.4.6 and 5.0.0 through 5.2.1 allows context-dependent attackers to execute arbitrary code by interrupting certain functions in the GD (ext/gd) extension and unspecified other extensions via a userspace error handler, which can be used to destroy and modify internal resources.

Double free vulnerability in the session extension in PHP 5.2.0 and 5.2.1 allows context-dependent attackers to execute arbitrary code via illegal characters in a session identifier, which is rejected by an internal session storage module, which calls the session identifier generator with an improper environment, leading to code execution when the generator is interrupted, as demonstrated by triggering a memory limit violation or certain PHP errors.

Double free vulnerability in PHP before 4.4.7, and 5.x before 5.2.2, allows context-dependent attackers to execute arbitrary code by interrupting the session_regenerate_id function, as demonstrated by calling a userspace error handler or triggering a memory limit violation.

The array_user_key_compare function in PHP 4.4.6 and earlier, and 5.x up to 5.2.1, makes erroneous calls to zval_dtor, which triggers memory corruption and allows local users to bypass safe_mode and execute arbitrary code via a certain unset operation after array_user_key_compare has been called.