http://googleprojectzero.blogspot.com.au/2015/03/exploiting-dram-rowhammer-bug-to-gain.html
“Rowhammer” is a problem with some recent DRAM devices in which repeatedly accessing a row of memory can cause bit flips in adjacent rows. […] One exploit uses rowhammer-induced bit flips to gain kernel privileges on x86-64 Linux when run as an unprivileged userland process.