CVE-2018-20836

Published: 7 May 2019

An issue was discovered in the Linux kernel before 4.20. There is a race condition in smp_task_timedout() and smp_task_done() in drivers/scsi/libsas/sas_expander.c, leading to a use-after-free.

From the Ubuntu Security Team

It was discovered that a race condition existed in the Serial Attached SCSI (SAS) implementation in the Linux kernel. A local attacker could possibly use this to cause a denial of service (system crash) or execute arbitrary code.

Notes

Author	Note
sbeattie	hard to see how this can be attacker controlled

Priority

Cvss 3 Severity Score

8.1

Score breakdown

Status

Package	Release	Status
linux Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-44.47)
	cosmic	Released (4.18.0-14.15)
	disco	Not vulnerable (4.19.0-12.13)
	trusty	Ignored (was needs-triage ESM criteria)
	upstream	Released (4.20~rc1)
	xenial	Released (4.4.0-157.185)
	Patches: Introduced by 2908d778ab3e244900c310974e1fc1c69066e450 Fixed by b90cd6f2b905905fb42671009dc0e27c310a16ae
linux-aws Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1032.34)
	cosmic	Released (4.18.0-1008.10)
	disco	Not vulnerable (4.18.0-1008.10)
	trusty	Ignored (was needed ESM criteria)
	upstream	Released (4.20~rc1)
	xenial	Released (4.4.0-1090.101)
linux-aws-hwe Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Released (4.15.0-1032.34~16.04.1)
linux-azure Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1037.39)
	cosmic	Released (4.18.0-1008.8)
	disco	Not vulnerable (4.18.0-1008.8)
	trusty	Ignored (was needs-triage ESM criteria)
	upstream	Released (4.20~rc1)
	xenial	Released (4.15.0-1037.39~16.04.1)
linux-azure-edge Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1037.39)
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Released (4.15.0-1037.39~16.04.1)
linux-euclid Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Ignored (end of life, was needs-triage)
linux-flo Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Ignored (abandoned)
linux-gcp Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1027.28)
	cosmic	Released (4.18.0-1006.7)
	disco	Not vulnerable (4.18.0-1006.7)
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Released (4.15.0-1027.28~16.04.1)
linux-gcp-edge Launchpad, Ubuntu, Debian	bionic	Released (4.18.0-1006.7~18.04.1)
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Does not exist
linux-gke Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Ignored (end of standard support)
linux-gke-4.15 Launchpad, Ubuntu, Debian	bionic	Not vulnerable (4.15.0-1030.32)
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Does not exist
linux-gke-5.0 Launchpad, Ubuntu, Debian	bionic	Not vulnerable (5.0.0-1011.11~18.04.1)
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Does not exist
linux-goldfish Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Ignored (end of life)
linux-grouper Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Does not exist
linux-hwe Launchpad, Ubuntu, Debian	bionic	Released (4.18.0-14.15~18.04.1)
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Released (4.15.0-45.48~16.04.1)
linux-hwe-edge Launchpad, Ubuntu, Debian	bionic	Not vulnerable (5.0.0-15.16~18.04.1)
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Released (4.15.0-45.48~16.04.1)
linux-kvm Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1029.29)
	cosmic	Released (4.18.0-1007.7)
	disco	Not vulnerable (4.18.0-1007.7)
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Released (4.4.0-1052.59)
linux-lts-trusty Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Does not exist
linux-lts-utopic Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Does not exist
linux-lts-vivid Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Does not exist
linux-lts-wily Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Does not exist
linux-lts-xenial Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Ignored (was needs-triage ESM criteria)
	upstream	Released (4.20~rc1)
	xenial	Does not exist
linux-maguro Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Does not exist
linux-mako Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Ignored (abandoned)
linux-manta Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Does not exist
linux-oem Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1033.38)
	cosmic	Released (4.15.0-1033.38)
	disco	Not vulnerable (4.15.0-1033.38)
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Ignored (end of standard support, was needs-triage)
linux-oracle Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1008.10)
	cosmic	Released (4.15.0-1008.10)
	disco	Not vulnerable (4.15.0-1008.10)
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Released (4.15.0-1008.10~16.04.1)
linux-raspi2 Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1031.33)
	cosmic	Released (4.18.0-1009.11)
	disco	Not vulnerable (4.18.0-1009.11)
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Released (4.4.0-1117.126)
linux-snapdragon Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1053.57)
	cosmic	Does not exist
	disco	Not vulnerable (5.0.0-1010.10)
	trusty	Does not exist
	upstream	Released (4.20~rc1)
	xenial	Released (4.4.0-1121.127)

Severity score breakdown

Parameter	Value
Base score	8.1
Attack vector	Network
Attack complexity	High
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	High
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References

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