readelf.c in file before 5.22, as used in the Fileinfo component in PHP before 5.4.37, 5.5.x before 5.5.21, and 5.6.x before 5.6.5, does not consider that pread calls sometimes read only a subset of the available data, which allows remote attackers to cause a denial of service (uninitialized memory access) or possibly have unspecified other impact via a crafted ELF file.