Stack-based buffer overflow in the phar_fix_filepath function in ext/phar/phar.c in PHP before 5.4.43, 5.5.x before 5.5.27, and 5.6.x before 5.6.11 allows remote attackers to cause a denial of service or possibly have unspecified other impact via a large length value, as demonstrated by mishandling of an e-mail attachment by the imap PHP extension.