CVE-2016-5195

Published: 19 October 2016

Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect handling of a copy-on-write (COW) feature to write to a read-only memory mapping, as exploited in the wild in October 2016, aka "Dirty COW."

From the Ubuntu Security Team

It was discovered that a race condition existed in the memory manager of the Linux kernel when handling copy-on-write breakage of private read-only memory mappings. A local attacker could use this to gain administrative privileges.

Notes

Author	Note
jdstrand	android kernels (flo, goldfish, grouper, maguro, mako and manta) are not supported on the Ubuntu Touch 14.10 and earlier preview kernels linux-lts-saucy no longer receives official support linux-lts-quantal no longer receives official support

Author

Note

jdstrand

android kernels (flo, goldfish, grouper, maguro, mako and manta) are
not supported on the Ubuntu Touch 14.10 and earlier preview kernels
linux-lts-saucy no longer receives official support
linux-lts-quantal no longer receives official support

Priority

Cvss 3 Severity Score

7.8

Score breakdown

Status

Package	Release	Status
linux Launchpad, Ubuntu, Debian	precise	Released (3.2.0-115.157)
	trusty	Released (3.13.0-100.147)
	upstream	Released (4.9~rc2)
	xenial	Released (4.4.0-45.66)
	yakkety	Released (4.8.0-26.28)
	zesty	Not vulnerable (4.8.0-26.28)
	Patches: Introduced by 0a27a14a62921b438bb6f33772690d345a089be6 Fixed by 19be0eaffa3ac7d8eb6784ad9bdbc7d67ed8e619
linux-armadaxp Launchpad, Ubuntu, Debian	precise	Does not exist (precise was released [3.2.0-1677.104])
	trusty	Does not exist
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
	This package is not directly supported by the Ubuntu Security Team
linux-aws Launchpad, Ubuntu, Debian	precise	Does not exist
	trusty	Not vulnerable (4.4.0-1002.2)
	upstream	Released (4.9~rc2)
	xenial	Not vulnerable (4.4.0-1001.10)
	yakkety	Does not exist
	zesty	Does not exist
linux-flo Launchpad, Ubuntu, Debian	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	upstream	Released (4.9~rc2)
	xenial	Ignored (abandoned)
	yakkety	Ignored (abandoned)
	zesty	Does not exist
linux-gke Launchpad, Ubuntu, Debian	precise	Does not exist
	trusty	Does not exist
	upstream	Released (4.9~rc2)
	xenial	Not vulnerable (4.4.0-1003.3)
	yakkety	Does not exist
	zesty	Does not exist
linux-goldfish Launchpad, Ubuntu, Debian	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	upstream	Released (4.9~rc2)
	xenial	Ignored (abandoned)
	yakkety	Ignored (abandoned)
	zesty	Ignored (abandoned)
linux-grouper Launchpad, Ubuntu, Debian	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-hwe Launchpad, Ubuntu, Debian	precise	Does not exist
	trusty	Does not exist
	upstream	Released (4.9~rc2)
	xenial	Not vulnerable (4.8.0-36.36~16.04.1)
	yakkety	Does not exist
	zesty	Does not exist
linux-hwe-edge Launchpad, Ubuntu, Debian	precise	Does not exist
	trusty	Does not exist
	upstream	Released (4.9~rc2)
	xenial	Not vulnerable (4.8.0-36.36~16.04.1)
	yakkety	Does not exist
	zesty	Does not exist
linux-linaro-omap Launchpad, Ubuntu, Debian	precise	Does not exist (precise was ignored [abandoned])
	trusty	Does not exist
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-linaro-shared Launchpad, Ubuntu, Debian	precise	Does not exist (precise was ignored [abandoned])
	trusty	Does not exist
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-linaro-vexpress Launchpad, Ubuntu, Debian	precise	Does not exist (precise was ignored [abandoned])
	trusty	Does not exist
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-quantal Launchpad, Ubuntu, Debian	precise	Does not exist (precise was ignored [end-of-life])
	trusty	Does not exist
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
	This package is not directly supported by the Ubuntu Security Team
linux-lts-raring Launchpad, Ubuntu, Debian	precise	Does not exist (precise was ignored [end-of-life])
	trusty	Does not exist
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-saucy Launchpad, Ubuntu, Debian	precise	Does not exist (precise was ignored [end-of-life])
	trusty	Does not exist
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
	This package is not directly supported by the Ubuntu Security Team
linux-lts-trusty Launchpad, Ubuntu, Debian	precise	Released (3.13.0-100.147~precise1)
	trusty	Does not exist
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-utopic Launchpad, Ubuntu, Debian	precise	Does not exist
	trusty	Does not exist (trusty was ignored [out of standard support])
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-vivid Launchpad, Ubuntu, Debian	precise	Does not exist
	trusty	Does not exist (trusty was released [3.19.0-73.81~14.04.1])
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-wily Launchpad, Ubuntu, Debian	precise	Does not exist
	trusty	Does not exist (trusty was ignored [out of standard support])
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-xenial Launchpad, Ubuntu, Debian	precise	Does not exist
	trusty	Released (4.4.0-45.66~14.04.1)
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-maguro Launchpad, Ubuntu, Debian	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-mako Launchpad, Ubuntu, Debian	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	upstream	Released (4.9~rc2)
	xenial	Ignored (abandoned)
	yakkety	Ignored (abandoned)
	zesty	Does not exist
linux-manta Launchpad, Ubuntu, Debian	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-qcm-msm Launchpad, Ubuntu, Debian	precise	Does not exist (precise was ignored [abandoned])
	trusty	Does not exist
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-raspi2 Launchpad, Ubuntu, Debian	precise	Does not exist
	trusty	Does not exist
	upstream	Released (4.9~rc2)
	xenial	Released (4.4.0-1029.36)
	yakkety	Released (4.8.0-1018.21)
	zesty	Not vulnerable (4.8.0-1017.20)
linux-snapdragon Launchpad, Ubuntu, Debian	precise	Does not exist
	trusty	Does not exist
	upstream	Released (4.9~rc2)
	xenial	Released (4.4.0-1032.36)
	yakkety	Released (4.4.0-1032.36)
	zesty	Not vulnerable (4.4.0-1032.36)
linux-ti-omap4 Launchpad, Ubuntu, Debian	precise	Does not exist (precise was released [3.2.0-1493.120])
	trusty	Does not exist
	upstream	Released (4.9~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist

Severity score breakdown

Parameter	Value
Base score	7.8
Attack vector	Local
Attack complexity	Low
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	High
Availability impact	High
Vector	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

Bugs

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1633547

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