Race condition in drivers/tty/n_hdlc.c in the Linux kernel through 4.10.1 allows local users to gain privileges or cause a denial of service (double free) by setting the HDLC line discipline. Alexander Popov discovered that the N_HDLC line discipline implementation in the Linux kernel contained a double-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly gain administrative privileges.