CVE-2018-18386 Denial of service in n/a

Low 3.3 Published 17 Oct 2018 Updated 5 Aug 2024

Local attackers can cause a denial of service by hanging pseudo terminal devices due to a logic error in the Linux kernel's TIOCINQ handling.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2018-18386?

CVE-2018-18386 is a low-severity denial of service vulnerability in Canonical Ubuntu Linux, published on 17 Oct 2018. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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.

Weakness: CWE-704

Which versions are affected by CVE-2018-18386?

It affects 2 products.

Linux distribution packages (20)

`kgraft-patch-SLE12-SP1_Update_23` SUSE:Linux Enterprise Server 12 SP1-LTSS	All versions	`10-2.1`
`kgraft-patch-SLE12-SP1_Update_24` SUSE:Linux Enterprise Server 12 SP1-LTSS	All versions	`9-2.1`
`kgraft-patch-SLE12-SP1_Update_25` SUSE:Linux Enterprise Server 12 SP1-LTSS	All versions	`9-2.1`
`kgraft-patch-SLE12-SP1_Update_26` SUSE:Linux Enterprise Server 12 SP1-LTSS	All versions	`9-2.1`
`kgraft-patch-SLE12-SP1_Update_27` SUSE:Linux Enterprise Server 12 SP1-LTSS	All versions	`7-2.1`
`kgraft-patch-SLE12-SP1_Update_28` SUSE:Linux Enterprise Server 12 SP1-LTSS	All versions	`6-2.1`
`kgraft-patch-SLE12-SP1_Update_29` SUSE:Linux Enterprise Server 12 SP1-LTSS	All versions	`6-2.1`
`kgraft-patch-SLE12-SP1_Update_30` SUSE:Linux Enterprise Server 12 SP1-LTSS	All versions	`5-2.1`
`kgraft-patch-SLE12-SP1_Update_31` SUSE:Linux Enterprise Server 12 SP1-LTSS	All versions	`3-2.1`
`kgraft-patch-SLE12-SP1_Update_32` SUSE:Linux Enterprise Server 12 SP1-LTSS	All versions	`3-2.1`
`kgraft-patch-SLE12_Update_29` SUSE:Linux Enterprise Server 12-LTSS	All versions	`11-2.1`
`kgraft-patch-SLE12_Update_30` SUSE:Linux Enterprise Server 12-LTSS	All versions	`10-2.1`
`kgraft-patch-SLE12_Update_31` SUSE:Linux Enterprise Server 12-LTSS	All versions	`10-2.1`
`kgraft-patch-SLE12_Update_32` SUSE:Linux Enterprise Server 12-LTSS	All versions	`10-2.1`
`kgraft-patch-SLE12_Update_33` SUSE:Linux Enterprise Server 12-LTSS	All versions	`9-2.1`
`kgraft-patch-SLE12_Update_34` SUSE:Linux Enterprise Server 12-LTSS	All versions	`7-2.1`
`kgraft-patch-SLE12_Update_35` SUSE:Linux Enterprise Server 12-LTSS	All versions	`6-2.1`
`kgraft-patch-SLE12_Update_36` SUSE:Linux Enterprise Server 12-LTSS	All versions	`6-2.1`
`kgraft-patch-SLE12_Update_37` SUSE:Linux Enterprise Server 12-LTSS	All versions	`5-2.1`
`kgraft-patch-SLE12_Update_38` SUSE:Linux Enterprise Server 12-LTSS	All versions	`3-2.1`

Products include Canonical Ubuntu Linux, Linux kernel.

How do I fix CVE-2018-18386?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2018-18386 being exploited?

There is no known exploitation of CVE-2018-18386 in the wild and no public exploit code.

All Canonical Ubuntu Linux vulnerabilities

Sources

Also known as DEBIAN-CVE-2018-18386, GHSA-j3hq-436j-w545, SUSE-SU-2018:3772-1, UBUNTU-CVE-2018-18386.