ext/phar/phar.c in PHP before 5.4.40, 5.5.x before 5.5.24, and 5.6.x before 5.6.8 allows remote attackers to obtain sensitive information from process memory or cause a denial of service (buffer over-read and application crash) via a crafted length value in conjunction with crafted serialized data in a phar archive, related to the phar_parse_metadata and phar_parse_pharfile functions.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.