The mcopy function in softmagic.c in file 5.x, as used in the Fileinfo component in PHP before 5.4.40, 5.5.x before 5.5.24, and 5.6.x before 5.6.8, does not properly restrict a certain offset value, which allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted string that is mishandled by a "Python script text executable" rule.