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CVE-2019-3016

Publication date 30 January 2020

Last updated 24 July 2024

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

4.7 · Medium

Score breakdown

In a Linux KVM guest that has PV TLB enabled, a process in the guest kernel may be able to read memory locations from another process in the same guest. This problem is limit to the host running linux kernel 4.10 with a guest running linux kernel 4.16 or later. The problem mainly affects AMD processors but Intel CPUs cannot be ruled out.

From the Ubuntu Security Team

It was discovered that the KVM implementation in the Linux kernel, when paravirtual TLB flushes are enabled in guests, the hypervisor in some situations could miss deferred TLB flushes or otherwise mishandle them. An attacker in a guest VM could use this to expose sensitive information (read memory from another guest VM).

Read the notes from the security team

Status

Package Ubuntu Release Status
linux 20.04 LTS focal
Not affected
19.10 eoan
Fixed 5.3.0-42.34
19.04 disco Ignored
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
linux-aws 20.04 LTS focal
Not affected
19.10 eoan
Fixed 5.3.0-1013.14
19.04 disco Ignored
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
linux-aws-5.0 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic
Fixed 5.0.0-1027.30
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-aws-hwe 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-azure 20.04 LTS focal
Not affected
19.10 eoan
Fixed 5.3.0-1016.17
19.04 disco Ignored
18.04 LTS bionic
Fixed 5.0.0-1035.37
16.04 LTS xenial
Not affected
14.04 LTS trusty Ignored
linux-azure-5.3 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic
Fixed 5.3.0-1016.17~18.04.1
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-azure-edge 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic Ignored
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-gcp 20.04 LTS focal
Not affected
19.10 eoan
Fixed 5.3.0-1014.15
19.04 disco Ignored
18.04 LTS bionic
Fixed 5.0.0-1033.34
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-gcp-5.3 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic
Fixed 5.3.0-1014.15~18.04.1
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gcp-edge 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic Ignored
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gke-4.15 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gke-5.0 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic
Fixed 5.0.0-1032.33
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gke-5.3 20.04 LTS focal Not in release
19.10 eoan Not in release
18.04 LTS bionic
Fixed 5.3.0-1014.15~18.04.1
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-hwe 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic
Fixed 5.3.0-42.34~18.04.1
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-hwe-edge 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic Ignored
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-kvm 20.04 LTS focal
Not affected
19.10 eoan
Fixed 5.3.0-1012.13
19.04 disco Ignored
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-lts-trusty 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco 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 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty
Not affected
linux-oem 20.04 LTS focal Not in release
19.10 eoan
Not affected
19.04 disco Ignored
18.04 LTS bionic
Not affected
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-oem-5.6 20.04 LTS focal
Not affected
19.10 eoan 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-osp1 20.04 LTS focal Not in release
19.10 eoan
Fixed 5.0.0-1043.48
19.04 disco Ignored
18.04 LTS bionic
Fixed 5.0.0-1043.48
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-oracle 20.04 LTS focal
Not affected
19.10 eoan
Fixed 5.3.0-1011.12
19.04 disco Ignored
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-oracle-5.0 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic
Fixed 5.0.0-1013.18
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-oracle-5.3 20.04 LTS focal Not in release
19.10 eoan Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-raspi2 20.04 LTS focal Ignored
19.10 eoan
Fixed 5.3.0-1019.21
19.04 disco Ignored
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-raspi2-5.3 20.04 LTS focal Not in release
19.10 eoan Not in release
18.04 LTS bionic
Fixed 5.3.0-1019.21~18.04.1
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-snapdragon 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Ignored
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release

Notes

tyhicks

This issue does not affect default installations of Ubuntu as the paravirtual TLB flush feature in KVM is not enabled by default. The QEMU CPU feature "kvm-pv-tlb-flush" is used to enable paravirtual TLB flush.

cascardo

It is thought that issue does not affect Intel processors *not* supporting Process-Context Identifiers (PCIDs). You can check support for PCIDs on systems with Intel processors by running "grep pcid /proc/cpuinfo" and verifying that "pcid" shows as one of the flags. it was mentioned that it was only easily reproducible on AMD CPUs.

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

References

Related Ubuntu Security Notices (USN)

    • USN-4301-1
    • Linux kernel vulnerabilities
    • 25 March 2020
    • USN-4300-1
    • Linux kernel vulnerabilities
    • 25 March 2020
    • LSN-0065-1
    • Kernel Live Patch Security Notice
    • 9 April 2020

Other references