CVE-2018-18955

Published: 16 November 2018

In the Linux kernel 4.15.x through 4.19.x before 4.19.2, map_write() in kernel/user_namespace.c allows privilege escalation because it mishandles nested user namespaces with more than 5 UID or GID ranges. A user who has CAP_SYS_ADMIN in an affected user namespace can bypass access controls on resources outside the namespace, as demonstrated by reading /etc/shadow. This occurs because an ID transformation takes place properly for the namespaced-to-kernel direction but not for the kernel-to-namespaced direction.

From the Ubuntu security team

Jann Horn discovered that the Linux kernel mishandles mapping UID or GID ranges inside nested user namespaces in some situations. A local attacker could use this to bypass access controls on resources outside the namespace.

Priority

Medium

CVSS 3 base score: 7.0

Status

Package Release Status
linux
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver)
Released (4.15.0-42.45)
Ubuntu 16.04 ESM (Xenial Xerus) Not vulnerable
(4.2.0-16.19)
Ubuntu 14.04 ESM (Trusty Tahr) Not vulnerable
(3.11.0-12.19)
Patches:
Introduced by 6397fac4915ab3002dc15aae751455da1a852f25
Fixed by d2f007dbe7e4c9583eea6eb04d60001e85c6f1bd
linux-aws
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver)
Released (4.15.0-1029.30)
Ubuntu 16.04 ESM (Xenial Xerus) Not vulnerable
(4.4.0-1001.10)
Ubuntu 14.04 ESM (Trusty Tahr) Not vulnerable
(4.4.0-1002.2)
linux-aws-hwe
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Does not exist

Ubuntu 16.04 ESM (Xenial Xerus) Not vulnerable
(4.15.0-1030.31~16.04.1)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

linux-azure
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver)
Released (4.15.0-1035.36)
Ubuntu 16.04 ESM (Xenial Xerus)
Released (4.15.0-1035.36~16.04.1)
Ubuntu 14.04 ESM (Trusty Tahr)
Released (4.15.0-1035.36~14.04.2)
linux-azure-edge
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver)
Released (4.15.0-1035.36)
Ubuntu 16.04 ESM (Xenial Xerus)
Released (4.15.0-1035.36~16.04.1)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

linux-euclid
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Does not exist

Ubuntu 16.04 ESM (Xenial Xerus) Not vulnerable
(4.4.0-9019.20)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

linux-flo
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Does not exist

Ubuntu 16.04 ESM (Xenial Xerus) Ignored
(abandoned)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist
(trusty was ignored [abandoned])
linux-gcp
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver)
Released (4.15.0-1025.26)
Ubuntu 16.04 ESM (Xenial Xerus)
Released (4.15.0-1025.26~16.04.1)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

linux-gcp-edge
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Not vulnerable
(4.18.0-1004.5~18.04.1)
Ubuntu 16.04 ESM (Xenial Xerus) Does not exist

Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

linux-gke
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Does not exist

Ubuntu 16.04 ESM (Xenial Xerus) Ignored
(end-of-life)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

linux-goldfish
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Does not exist

Ubuntu 16.04 ESM (Xenial Xerus) Ignored
(end-of-life)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist
(trusty was ignored [abandoned])
linux-grouper
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Does not exist

Ubuntu 16.04 ESM (Xenial Xerus) Does not exist

Ubuntu 14.04 ESM (Trusty Tahr) Does not exist
(trusty was ignored [abandoned])
linux-hwe
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Not vulnerable
(4.18.0-13.14~18.04.1)
Ubuntu 16.04 ESM (Xenial Xerus)
Released (4.15.0-42.45~16.04.1)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

linux-hwe-edge
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Not vulnerable
(4.18.0-12.13~18.04.1)
Ubuntu 16.04 ESM (Xenial Xerus)
Released (4.15.0-42.45~16.04.1)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

linux-kvm
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver)
Released (4.15.0-1027.27)
Ubuntu 16.04 ESM (Xenial Xerus) Not vulnerable
(4.4.0-1004.9)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

linux-lts-trusty
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Does not exist

Ubuntu 16.04 ESM (Xenial Xerus) Does not exist

Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

linux-lts-utopic
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Does not exist

Ubuntu 16.04 ESM (Xenial Xerus) Does not exist

Ubuntu 14.04 ESM (Trusty Tahr) Does not exist
(trusty was ignored [out of standard support])
linux-lts-vivid
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Does not exist

Ubuntu 16.04 ESM (Xenial Xerus) Does not exist

Ubuntu 14.04 ESM (Trusty Tahr) Does not exist
(trusty was ignored [out of standard support])
linux-lts-wily
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Does not exist

Ubuntu 16.04 ESM (Xenial Xerus) Does not exist

Ubuntu 14.04 ESM (Trusty Tahr) Does not exist
(trusty was ignored [out of standard support])
linux-lts-xenial
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Does not exist

Ubuntu 16.04 ESM (Xenial Xerus) Does not exist

Ubuntu 14.04 ESM (Trusty Tahr) Not vulnerable
(4.4.0-13.29~14.04.1)
linux-maguro
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Does not exist

Ubuntu 16.04 ESM (Xenial Xerus) Does not exist

Ubuntu 14.04 ESM (Trusty Tahr) Does not exist
(trusty was ignored [abandoned])
linux-mako
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Does not exist

Ubuntu 16.04 ESM (Xenial Xerus) Ignored
(abandoned)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist
(trusty was ignored [abandoned])
linux-manta
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Does not exist

Ubuntu 16.04 ESM (Xenial Xerus) Does not exist

Ubuntu 14.04 ESM (Trusty Tahr) Does not exist
(trusty was ignored [abandoned])
linux-oem
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver)
Released (4.15.0-1028.33)
Ubuntu 16.04 ESM (Xenial Xerus) Ignored
(was needs-triage now end-of-life)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

linux-oracle
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Not vulnerable
(4.15.0-1007.9)
Ubuntu 16.04 ESM (Xenial Xerus) Not vulnerable
(4.15.0-1007.9~16.04.1)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

linux-raspi2
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver)
Released (4.15.0-1029.31)
Ubuntu 16.04 ESM (Xenial Xerus) Not vulnerable
(4.2.0-1013.19)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

linux-snapdragon
Launchpad, Ubuntu, Debian
Upstream
Released (4.20~rc2)
Ubuntu 18.04 LTS (Bionic Beaver) Not vulnerable

Ubuntu 16.04 ESM (Xenial Xerus) Not vulnerable
(4.4.0-1012.12)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist