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

Integer overflows in (1) base64encode and (2) the GD library for PHP before 4.3.3 have unknown impact and unknown attack vectors.

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/zendalloc.c).

The deserialization code in PHP before 4.3.10 and PHP 5.x up to 5.0.2 allows remote attackers to cause a denial of service and execute arbitrary code via untrusted data to the unserialize function that may trigger "information disclosure, double-free and negative reference index array underflow" results.

Buffer overflow in the exifreaddata function in PHP before 4.3.10 and PHP 5.x up to 5.0.2 allows remote attackers to execute arbitrary code via a long section name in an image file.

zendhashdelkeyorindex in zendhash.c in PHP before 4.4.3 and 5.x before 5.1.3 can cause zendhashdel to delete the wrong element, which prevents a variable from being unset even when the PHP unset function is called, which might cause the variable's value to be used in security-relevant operations.

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) safemode or (2) openbasedir functions, and when used in applications that accept user-controlled input for the mailbox argument to the imapopen function, allow remote attackers to obtain access to an IMAP stream data structure and conduct unauthorized IMAP actions.

PHP 4.x and 5.x before 5.2.1, when running on multi-threaded systems, does not ensure thread safety for libc crypt function calls using protection schemes such as a mutex, which creates race conditions that allow remote attackers to overwrite internal program memory and gain system access.

Unspecified vulnerability in PHP before 5.2.1 allows attackers to "clobber" certain super-global variables via unspecified vectors.