CVE-2018-16882

Publication date 3 January 2019

Last updated 24 July 2024

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

8.8 · High

Score breakdown

A use-after-free issue was found in the way the Linux kernel's KVM hypervisor processed posted interrupts when nested(=1) virtualization is enabled. In nested_get_vmcs12_pages(), in case of an error while processing posted interrupt address, it unmaps the 'pi_desc_page' without resetting 'pi_desc' descriptor address, which is later used in pi_test_and_clear_on(). A guest user/process could use this flaw to crash the host kernel resulting in DoS or potentially gain privileged access to a system. Kernel versions before 4.14.91 and before 4.19.13 are vulnerable.

From the Ubuntu Security Team

Cfir Cohen discovered that a use-after-free vulnerability existed in the KVM implementation of the Linux kernel, when handling interrupts in environments where nested virtualization is in use (nested KVM virtualization is not enabled by default in Ubuntu kernels). A local attacker in a guest VM could possibly use this to gain administrative privileges in a host machine.

Read the notes from the security team

Status

Package Ubuntu Release Status
linux 18.10 cosmic
Fixed 4.18.0-14.15
18.04 LTS bionic
Fixed 4.15.0-44.47
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
linux-aws 18.10 cosmic
Fixed 4.18.0-1008.10
18.04 LTS bionic
Fixed 4.15.0-1032.34
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
linux-aws-hwe 18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial
Fixed 4.15.0-1032.34~16.04.1
14.04 LTS trusty Not in release
linux-azure 18.10 cosmic
Fixed 4.18.0-1008.8
18.04 LTS bionic
Fixed 4.15.0-1037.39
16.04 LTS xenial
Fixed 4.15.0-1037.39~16.04.1
14.04 LTS trusty
Fixed 4.15.0-1037.39~14.04.2
linux-azure-edge 18.10 cosmic Not in release
18.04 LTS bionic
Fixed 4.15.0-1037.39
16.04 LTS xenial
Fixed 4.15.0-1037.39~16.04.1
14.04 LTS trusty Not in release
linux-euclid 18.10 cosmic Not in release
18.04 LTS bionic 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
16.04 LTS xenial Ignored abandoned
14.04 LTS trusty Not in release
linux-gcp 18.10 cosmic
Fixed 4.18.0-1006.7
18.04 LTS bionic
Fixed 4.15.0-1027.28
16.04 LTS xenial
Fixed 4.15.0-1027.28~16.04.1
14.04 LTS trusty Not in release
linux-gcp-edge 18.10 cosmic Not in release
18.04 LTS bionic
Fixed 4.18.0-1006.7~18.04.1
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gke 18.10 cosmic Not in release
18.04 LTS bionic 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
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
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
Fixed 4.18.0-14.15~18.04.1
16.04 LTS xenial
Fixed 4.15.0-45.48~16.04.1
14.04 LTS trusty Not in release
linux-hwe-edge 18.10 cosmic Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial
Fixed 4.15.0-45.48~16.04.1
14.04 LTS trusty Not in release
linux-kvm 18.10 cosmic
Fixed 4.18.0-1007.7
18.04 LTS bionic
Fixed 4.15.0-1029.29
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
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
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
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
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
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
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
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
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-oem 18.10 cosmic
Fixed 4.15.0-1033.38
18.04 LTS bionic
Fixed 4.15.0-1033.38
16.04 LTS xenial Ignored end of standard support, was needs-triage
14.04 LTS trusty Not in release
linux-oracle 18.10 cosmic
Not affected
18.04 LTS bionic
Fixed 4.15.0-1008.10
16.04 LTS xenial
Fixed 4.15.0-1008.10~16.04.1
14.04 LTS trusty Not in release
linux-raspi2 18.10 cosmic
Fixed 4.18.0-1009.11
18.04 LTS bionic
Fixed 4.15.0-1031.33
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
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 8.8 · High
Attack vector Local
Attack complexity Low
Privileges required Low
User interaction None
Scope Changed
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

References

Related Ubuntu Security Notices (USN)

    • USN-3878-1
    • Linux kernel vulnerabilities
    • 4 February 2019
    • USN-3871-4
    • Linux kernel (HWE) vulnerabilities
    • 4 February 2019
    • USN-3871-1
    • Linux kernel vulnerabilities
    • 29 January 2019
    • USN-3871-5
    • Linux kernel (Azure) vulnerabilities
    • 7 February 2019
    • USN-3872-1
    • Linux kernel (HWE) vulnerabilities
    • 29 January 2019
    • USN-3878-2
    • Linux kernel (Azure) vulnerabilities
    • 7 February 2019
    • USN-3871-3
    • Linux kernel (AWS, GCP, KVM, OEM, Raspberry Pi 2) vulnerabilities
    • 4 February 2019

Other references