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.

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 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.

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.

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.

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.

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.

The zip:// URL wrapper provided by the PECL zip extension in PHP before 4.4.7, and 5.2.0 and 5.2.1, does not implement safemode or open_basedir checks, which allows remote attackers to read ZIP archives located outside of the intended directories.

The compress.bzip2:// URL wrapper provided by the bz2 extension in PHP before 4.4.7, and 5.x before 5.2.2, does not implement safemode or open_basedir checks, which allows remote attackers to read bzip2 archives located outside of the intended directories.

Buffer overflow in the snmpget function in the snmp extension in PHP 5.2.3 and earlier, including PHP 4.4.6 and probably other PHP 4 versions, allows context-dependent attackers to execute arbitrary code via a long value in the third argument (object id).

The import_request_variables function in PHP 4.0.7 through 4.4.6, and 5.x before 5.2.2, when called without a prefix, does not prevent the (1) GET, (2) POST, (3) COOKIE, (4) FILES, (5) SERVER, (6) SESSION, and other superglobals from being overwritten, which allows remote attackers to spoof source IP address and Referer data, and have other unspecified impact. NOTE: it could be argued that this is a design limitation of PHP and that only the misuse of this feature, i.e. implementation bugs in applications, should be included in CVE. However, it has been fixed by the vendor.

Stack-based buffer overflow in the zip:// URL wrapper in PECL ZIP 1.8.3 and earlier, as bundled with PHP 5.2.0 and 5.2.1, allows remote attackers to execute arbitrary code via a long zip:// URL, as demonstrated by actively triggering URL access from a remote PHP interpreter via avatar upload or blog pingback.

Integer overflow in the substr_compare function in PHP 5.2.1 and earlier allows context-dependent attackers to read sensitive memory via a large value in the length argument, a different vulnerability than CVE-2006-1991.

The Zend Engine in PHP 4.x before 4.4.7, and 5.x before 5.2.2, allows remote attackers to cause a denial of service (stack exhaustion and PHP crash) via deeply nested arrays, which trigger deep recursion in the variable destruction routines.

Off-by-one error in the str_ireplace function in PHP 5.2.1 might allow context-dependent attackers to cause a denial of service (crash).