The phar_parse_metadata function in 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 cause a denial of service (heap metadata corruption) or possibly have unspecified other impact via a crafted tar archive.
Exploitability
AV:NAC:LAu:NImpact
C:PI:PA:P7.5/AV:N/AC:L/Au:N/C:P/I:P/A:P