CVE-2019-6974

Published: 15 February 2019

In the Linux kernel before 4.20.8, kvm_ioctl_create_device in virt/kvm/kvm_main.c mishandles reference counting because of a race condition, leading to a use-after-free.

From the Ubuntu Security Team

Jann Horn discovered that the KVM implementation in the Linux kernel contained a use-after-free vulnerability. An attacker in a guest VM with access to /dev/kvm could use this to cause a denial of service (guest VM crash).

Priority

Cvss 3 Severity Score

8.1

Score breakdown

Status

Package	Release	Status
linux Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-47.50)
	cosmic	Released (4.18.0-17.18)
	disco	Not vulnerable (5.0.0-7.8)
	trusty	Released (3.13.0-168.218)
	upstream	Released (5.0~rc6)
	xenial	Released (4.4.0-145.171)
	Patches: Introduced by 852b6d57dc7fa378019786fa84727036e56839ea Fixed by cfa39381173d5f969daf43582c95ad679189cbc9
linux-aws Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1035.37)
	cosmic	Released (4.18.0-1012.14)
	disco	Not vulnerable (5.0.0-1001.1)
	trusty	Released (4.4.0-1040.43)
	upstream	Released (5.0~rc6)
	xenial	Released (4.4.0-1079.89)
linux-aws-hwe Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc6)
	xenial	Released (4.15.0-1035.37~16.04.1)
linux-azure Launchpad, Ubuntu, Debian	bionic	Released (4.18.0-1014.14~18.04.1)
	cosmic	Released (4.18.0-1014.14)
	disco	Not vulnerable (5.0.0-1001.1)
	trusty	Released (4.15.0-1041.45~14.04.1)
	upstream	Released (5.0~rc6)
	xenial	Released (4.15.0-1041.45)
linux-azure-edge Launchpad, Ubuntu, Debian	bionic	Released (4.18.0-1014.14~18.04.1)
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc6)
	xenial	Released (4.15.0-1041.45)
linux-euclid Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc6)
	xenial	Ignored (was needed ESM criteria)
linux-flo Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist (trusty was ignored [abandoned])
	upstream	Released (5.0~rc6)
	xenial	Ignored (abandoned)
linux-gcp Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1029.31)
	cosmic	Released (4.18.0-1008.9)
	disco	Not vulnerable (5.0.0-1001.1)
	trusty	Does not exist
	upstream	Released (5.0~rc6)
	xenial	Released (4.15.0-1029.31~16.04.1)
linux-gcp-edge Launchpad, Ubuntu, Debian	bionic	Released (4.18.0-1008.9~18.04.1)
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc6)
	xenial	Does not exist
linux-gke Launchpad, Ubuntu, Debian	bionic	Not vulnerable
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc6)
	xenial	Ignored (end of standard support)
linux-goldfish Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist (trusty was ignored [abandoned])
	upstream	Released (5.0~rc6)
	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 (trusty was ignored [abandoned])
	upstream	Released (5.0~rc6)
	xenial	Does not exist
linux-hwe Launchpad, Ubuntu, Debian	bionic	Released (4.18.0-17.18~18.04.1)
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc6)
	xenial	Released (4.15.0-47.50~16.04.1)
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 (5.0~rc6)
	xenial	Released (4.15.0-47.50~16.04.1)
linux-kvm Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1031.31)
	cosmic	Released (4.18.0-1009.9)
	disco	Not vulnerable (5.0.0-1001.1)
	trusty	Does not exist
	upstream	Released (5.0~rc6)
	xenial	Released (4.4.0-1043.49)
linux-lts-trusty Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist
	upstream	Released (5.0~rc6)
	xenial	Does not exist
linux-lts-utopic Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Ignored (end of life, was ignored)
	upstream	Released (5.0~rc6)
	xenial	Does not exist
linux-lts-vivid Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Ignored (end of life, was ignored)
	upstream	Released (5.0~rc6)
	xenial	Does not exist
linux-lts-wily Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Ignored (end of life, was ignored)
	upstream	Released (5.0~rc6)
	xenial	Does not exist
linux-lts-xenial Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Released (4.4.0-144.170~14.04.1)
	upstream	Released (5.0~rc6)
	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 (trusty was ignored [abandoned])
	upstream	Released (5.0~rc6)
	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 (trusty was ignored [abandoned])
	upstream	Released (5.0~rc6)
	xenial	Ignored (abandoned)
linux-manta Launchpad, Ubuntu, Debian	bionic	Does not exist
	cosmic	Does not exist
	disco	Does not exist
	trusty	Does not exist (trusty was ignored [abandoned])
	upstream	Released (5.0~rc6)
	xenial	Does not exist
linux-oem Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1035.40)
	cosmic	Released (4.15.0-1035.40)
	disco	Not vulnerable (4.15.0-1035.40)
	trusty	Does not exist
	upstream	Released (5.0~rc6)
	xenial	Ignored (end of standard support, was needs-triage)
linux-oracle Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1010.12)
	cosmic	Released (4.15.0-1010.12)
	disco	Not vulnerable (4.15.0-1010.12)
	trusty	Does not exist
	upstream	Released (5.0~rc6)
	xenial	Released (4.15.0-1010.12~16.04.1)
linux-raspi2 Launchpad, Ubuntu, Debian	bionic	Released (4.15.0-1033.35)
	cosmic	Released (4.18.0-1011.13)
	disco	Not vulnerable (5.0.0-1004.4)
	trusty	Does not exist
	upstream	Released (5.0~rc6)
	xenial	Released (4.4.0-1106.114)
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 (5.0~rc6)
	xenial	Released (4.4.0-1110.115)

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

Bugs

https://bugs.chromium.org/p/project-zero/issues/detail?id=1765

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