Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect handling of a copy-on-write (COW) feature to write to a read-only memory mapping, as exploited in the wild in October 2016, aka "Dirty COW."
The rio_ioctl function in drivers/net/ethernet/dlink/dl2k.c in the Linux kernel before 3.3.7 does not restrict access to the SIOCSMIIREG command, which allows local users to write data to an Ethernet adapter via an ioctl call.