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.