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.
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-18386.json"