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CVE-2018-12904

Publication date 27 June 2018

Last updated 24 July 2024

Ubuntu priority

Low

Why this priority?

Cvss 3 Severity Score

4.9 · Medium

Score breakdown

In arch/x86/kvm/vmx.c in the Linux kernel before 4.17.2, when nested virtualization is used, local attackers could cause L1 KVM guests to VMEXIT, potentially allowing privilege escalations and denial of service attacks due to lack of checking of CPL.

From the Ubuntu Security Team

Felix Wilhelm discovered that the KVM implementation in the Linux kernel did not properly perform permission checks in some situations when nested virtualization is used. An attacker in a guest VM could possibly use this to escape into an outer VM or the host OS.

Read the notes from the security team

Status

Package Ubuntu Release Status
linux 18.10 cosmic
Not affected
18.04 LTS bionic
Fixed 4.15.0-33.36
17.10 artful Ignored end of life
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
linux-aws 18.10 cosmic
Not affected
18.04 LTS bionic
Fixed 4.15.0-1020.20
17.10 artful Not in release
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
linux-azure 18.10 cosmic
Not affected
18.04 LTS bionic
Fixed 4.15.0-1022.23
17.10 artful Not in release
16.04 LTS xenial
Fixed 4.15.0-1022.22~16.04.1
14.04 LTS trusty
Not affected
linux-azure-edge 18.10 cosmic Not in release
18.04 LTS bionic
Not affected
17.10 artful Not in release
16.04 LTS xenial
Fixed 4.15.0-1022.23
14.04 LTS trusty Not in release
linux-euclid 18.10 cosmic Not in release
18.04 LTS bionic Not in release
17.10 artful Not in release
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-flo 18.10 cosmic Not in release
18.04 LTS bionic Not in release
17.10 artful Not in release
16.04 LTS xenial Ignored abandoned
14.04 LTS trusty Not in release
linux-gcp 18.10 cosmic
Not affected
18.04 LTS bionic
Fixed 4.15.0-1018.19
17.10 artful Not in release
16.04 LTS xenial
Fixed 4.15.0-1018.19~16.04.2
14.04 LTS trusty Not in release
linux-gke 18.10 cosmic Not in release
18.04 LTS bionic Not in release
17.10 artful Not in release
16.04 LTS xenial Ignored end of standard support
14.04 LTS trusty Not in release
linux-goldfish 18.10 cosmic Not in release
18.04 LTS bionic Not in release
17.10 artful Not in release
16.04 LTS xenial Ignored end of life
14.04 LTS trusty Not in release
linux-grouper 18.10 cosmic Not in release
18.04 LTS bionic Not in release
17.10 artful Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-hwe 18.10 cosmic Not in release
18.04 LTS bionic
Not affected
17.10 artful Not in release
16.04 LTS xenial
Fixed 4.15.0-33.36~16.04.1
14.04 LTS trusty Not in release
linux-hwe-edge 18.10 cosmic Not in release
18.04 LTS bionic
Not affected
17.10 artful Not in release
16.04 LTS xenial
Fixed 4.15.0-33.36~16.04.1
14.04 LTS trusty Not in release
linux-kvm 18.10 cosmic
Not affected
18.04 LTS bionic
Fixed 4.15.0-1020.20
17.10 artful Not in release
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-lts-trusty 18.10 cosmic Not in release
18.04 LTS bionic Not in release
17.10 artful Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-lts-utopic 18.10 cosmic Not in release
18.04 LTS bionic Not in release
17.10 artful Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-lts-vivid 18.10 cosmic Not in release
18.04 LTS bionic Not in release
17.10 artful Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-lts-wily 18.10 cosmic Not in release
18.04 LTS bionic Not in release
17.10 artful Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-lts-xenial 18.10 cosmic Not in release
18.04 LTS bionic Not in release
17.10 artful Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty
Not affected
linux-maguro 18.10 cosmic Not in release
18.04 LTS bionic Not in release
17.10 artful Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-mako 18.10 cosmic Not in release
18.04 LTS bionic Not in release
17.10 artful Not in release
16.04 LTS xenial Ignored abandoned
14.04 LTS trusty Not in release
linux-manta 18.10 cosmic Not in release
18.04 LTS bionic Not in release
17.10 artful Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-oem 18.10 cosmic
Not affected
18.04 LTS bionic
Fixed 4.15.0-1017.20
17.10 artful Not in release
16.04 LTS xenial Ignored end of standard support, was needed
14.04 LTS trusty Not in release
linux-raspi2 18.10 cosmic
Not affected
18.04 LTS bionic
Fixed 4.15.0-1021.23
17.10 artful Ignored end of life
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-snapdragon 18.10 cosmic Not in release
18.04 LTS bionic
Not affected
17.10 artful
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release

Notes

tyhicks

Ubuntu kernels do not enable nested KVM virtualization by default and are unaffected by this flaw in the default configuration. To ensure that nested virtualization is not enabled, verify that the /sys/module/kvm_intel/parameters/nested file contains "N".

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
linux

Severity score breakdown

Parameter Value
Base score 4.9 · Medium
Attack vector Local
Attack complexity High
Privileges required None
User interaction None
Scope Unchanged
Confidentiality Low
Integrity impact Low
Availability impact Low
Vector CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

References

Related Ubuntu Security Notices (USN)

    • USN-3752-2
    • Linux kernel (HWE) vulnerabilities
    • 24 August 2018
    • USN-3752-1
    • Linux kernel vulnerabilities
    • 24 August 2018
    • USN-3752-3
    • Linux kernel (Azure, GCP, OEM) vulnerabilities
    • 28 August 2018

Other references