drivers/tty/n_tty.c in the Linux kernel before 4.14.11 allows local attackers (who are able to access pseudo terminals) to hang/block further usage of any pseudo terminal devices due to an EXTPROC versus ICANON confusion in TIOCINQ.
3.13.0-164.2144.4.0-1016.164.4.0-119.143~14.04.14.4.0-119.1434.4.0-1054.634.15.0-1013.13~16.04.24.15.0-1014.14~16.04.14.15.0-24.26~16.04.14.4.0-1020.254.4.0-1086.94Exploitability
AV:LAC:LPR:LUI:NScope
S:UImpact
C:NI:NA:LCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L