CVE-2018-20784

Published: 22 February 2019

In the Linux kernel before 4.20.2, kernel/sched/fair.c mishandles leaf cfs_rq's, which allows attackers to cause a denial of service (infinite loop in update_blocked_averages) or possibly have unspecified other impact by inducing a high load.

From the Ubuntu Security Team

Zhipeng Xie discovered that an infinite loop could be triggered in the CFS Linux kernel process scheduler. A local attacker could possibly use this to cause a denial of service.

Priority

Cvss 3 Severity Score

9.8

Score breakdown

Status

Package	Release	Status
linux Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-60.67)
	cosmic	Ignored (end of life)
	disco	Not vulnerable (4.19.0-12.13)
	eoan	Not vulnerable (5.0.0-13.14)
	trusty	Not vulnerable (3.11.0-12.19)
	upstream	Released (5.0~rc1)
	xenial	Released (4.4.0-170.199)
	Patches: Introduced by a9e7f6544b9cebdae54d29f87a7ba2a83c0471b5 Fixed by c40f7d74c741a907cfaeb73a7697081881c497d0
linux-aws Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1047.49)
	cosmic	Ignored (end of life)
	disco	Not vulnerable (5.0.0-1001.1)
	eoan	Not vulnerable (5.0.0-1004.4)
	trusty	Released (4.4.0-1059.63) Available with Ubuntu Pro or Ubuntu Pro (Infra-only)
	upstream	Released (5.0~rc1)
	xenial	Released (4.4.0-1099.110)
linux-aws-5.0 Launchpad, Ubuntu, Debian	bionic	Not vulnerable (5.0.0-1021.24~18.04.1)
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-aws-hwe Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Released (4.15.0-1047.49~16.04.1)
linux-azure Launchpad, Ubuntu, Debian	bionic	Released (5.0.0-1014.14~18.04.1)
	cosmic	Ignored (end of life)
	disco	Not vulnerable (5.0.0-1001.1)
	eoan	Not vulnerable (5.0.0-1004.4)
	trusty	Ignored (was needed ESM criteria)
	upstream	Released (5.0~rc1)
	xenial	Released (4.15.0-1056.61)
linux-azure-5.3 Launchpad, Ubuntu, Debian	bionic	Not vulnerable (5.3.0-1007.8~18.04.1)
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-azure-edge Launchpad, Ubuntu, Debian	bionic	Released (5.0.0-1014.14~18.04.1)
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Released (4.15.0-1056.61)
linux-euclid Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Ignored (was needed ESM criteria)
linux-flo Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist (trusty was ignored [abandoned])
	upstream	Released (5.0~rc1)
	xenial	Ignored (abandoned)
linux-gcp Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1042.45)
	cosmic	Ignored (end of life)
	disco	Not vulnerable (5.0.0-1001.1)
	eoan	Not vulnerable (5.0.0-1004.4)
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Released (4.15.0-1041.43)
linux-gcp-5.3 Launchpad, Ubuntu, Debian	bionic	Not vulnerable (5.3.0-1008.9~18.04.1)
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-gcp-edge Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1042.45)
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-gke Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Ignored (end of standard support)
linux-gke-4.15 Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1041.43)
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~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
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-goldfish Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist (trusty was ignored [abandoned])
	upstream	Released (5.0~rc1)
	xenial	Ignored (end of life)
linux-grouper Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist (trusty was ignored [abandoned])
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-hwe Launchpad, Ubuntu, Debian	bionic	Released (5.0.0-23.24~18.04.1)
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Released (4.15.0-60.67~16.04.1)
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
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Released (4.15.0-60.67~16.04.1)
linux-kvm Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1043.43)
	cosmic	Ignored (end of life)
	disco	Not vulnerable (5.0.0-1001.1)
	eoan	Not vulnerable (5.0.0-1004.4)
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Released (4.4.0-1063.70)
linux-lts-trusty Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-lts-utopic Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Ignored (end of life, was ignored)
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-lts-vivid Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Ignored (end of life, was ignored)
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-lts-wily Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Ignored (end of life, was ignored)
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-lts-xenial Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Released (4.4.0-170.199~14.04.1) Available with Ubuntu Pro or Ubuntu Pro (Infra-only)
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-maguro Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist (trusty was ignored [abandoned])
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-mako Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist (trusty was ignored [abandoned])
	upstream	Released (5.0~rc1)
	xenial	Ignored (abandoned)
linux-manta Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist (trusty was ignored [abandoned])
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-oem Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1056.65)
	cosmic	Ignored (end of life)
	disco	Ignored (end of life, was pending)
	eoan	Released (4.15.0-1059.68)
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Ignored (end of standard support, was needs-triage)
linux-oem-5.4 Launchpad, Ubuntu, Debian	bionic	Does not exist
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-oem-osp1 Launchpad, Ubuntu, Debian	bionic	Not vulnerable (5.0.0-1010.11)
	disco	Not vulnerable (5.0.0-1010.11)
	eoan	Not vulnerable (5.0.0-1010.11)
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-oracle Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1022.25)
	cosmic	Ignored (end of life)
	disco	Released (5.0.0-1004.8)
	eoan	Not vulnerable (5.3.0-1002.2)
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Released (4.15.0-1022.25~16.04.1)
linux-oracle-5.0 Launchpad, Ubuntu, Debian	bionic	Not vulnerable (5.0.0-1007.12~18.04.1)
	disco	Does not exist
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-raspi2 Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1044.47)
	cosmic	Ignored (end of life)
	disco	Not vulnerable (5.0.0-1004.4)
	eoan	Not vulnerable (5.0.0-1006.6)
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Released (4.4.0-1126.135)
linux-raspi2-5.3 Launchpad, Ubuntu, Debian	bionic	Not vulnerable (5.3.0-1017.19~18.04.1)
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Does not exist
linux-snapdragon Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1062.69)
	cosmic	Does not exist
	disco	Not vulnerable (5.0.0-1010.10)
	eoan	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc1)
	xenial	Released (4.4.0-1130.138)

Severity score breakdown

Parameter	Value
Base score	9.8
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	High
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

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