The unpacker::redirect_stdio function in unpack.cpp in unpack200 in OpenJDK 6, 7, and 8; Oracle Java SE 5.0u61, 6u71, 7u51, and 8; JRockit R27.8.1 and R28.3.1; and Java SE Embedded 7u51 does not securely create temporary files when a log file cannot be opened, which allows local users to overwrite arbitrary files via a symlink attack on /tmp/unpack.log.