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://access.redhat.com/errata/RHSA-2019:0831
https://bugzilla.suse.com/show_bug.cgi?id=1094825
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.11
https://github.com/torvalds/linux/commit/966031f340185eddd05affcf72b740549f056348
Source: MITRE
Published: 2018-10-17
Updated: 2019-04-23
Type: CWE-704
Base Score: 2.1
Vector: AV:L/AC:L/Au:N/C:N/I:N/A:P
Impact Score: 2.9
Exploitability Score: 3.9
Severity: LOW
Base Score: 3.3
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Impact Score: 1.4
Exploitability Score: 1.8
Severity: LOW