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CVE-2020-27777

Publication date 15 December 2020

Last updated 24 July 2024

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

6.7 · Medium

Score breakdown

A flaw was found in the way RTAS handled memory accesses in userspace to kernel communication. On a locked down (usually due to Secure Boot) guest system running on top of PowerVM or KVM hypervisors (pseries platform) a root like local user could use this flaw to further increase their privileges to that of a running kernel.

From the Ubuntu Security Team

Daniel Axtens discovered that PowerPC RTAS implementation in the Linux kernel did not properly restrict memory accesses in some situations. A privileged local attacker could use this to arbitrarily modify kernel memory, potentially bypassing kernel lockdown restrictions.

Read the notes from the security team

Status

Package Ubuntu Release Status
linux 20.10 groovy
Fixed 5.8.0-44.50
20.04 LTS focal
Fixed 5.4.0-59.65
18.04 LTS bionic
Fixed 4.15.0-129.132
16.04 LTS xenial
Fixed 4.4.0-201.233
14.04 LTS trusty Ignored
linux-aws 20.10 groovy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
linux-aws-5.0 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-aws-5.3 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-aws-5.4 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-aws-hwe 20.10 groovy Not in release
20.04 LTS focal 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 20.10 groovy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
linux-azure-4.15 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-azure-5.3 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-azure-5.4 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-azure-edge 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-dell300x 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Fixed 4.15.0-1010.14
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gcp 20.10 groovy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-gcp-4.15 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gcp-5.3 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gcp-5.4 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gcp-edge 20.10 groovy Not in release
20.04 LTS focal 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-4.15 20.10 groovy Not in release
20.04 LTS focal 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 20.10 groovy Not in release
20.04 LTS focal 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-5.3 20.10 groovy Not in release
20.04 LTS focal 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-5.4 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Fixed 5.4.0-1033.35~18.04.1
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gkeop 20.10 groovy Not in release
20.04 LTS focal
Not affected
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gkeop-5.4 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Fixed 5.4.0-1008.9~18.04.1
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-hwe 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic Ignored
16.04 LTS xenial
Fixed 4.15.0-129.132~16.04.1
14.04 LTS trusty Not in release
linux-hwe-5.4 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Fixed 5.4.0-59.65~18.04.1
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-hwe-5.8 20.10 groovy Not in release
20.04 LTS focal
Fixed 5.8.0-44.50~20.04.1
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-hwe-edge 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic Ignored
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-kvm 20.10 groovy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-lts-trusty 20.10 groovy Not in release
20.04 LTS focal 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 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty
linux-oem 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-oem-5.10 20.10 groovy Not in release
20.04 LTS focal
Not affected
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-oem-5.6 20.10 groovy Not in release
20.04 LTS focal
Not affected
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-oem-osp1 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-oracle 20.10 groovy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-oracle-5.0 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-oracle-5.3 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-oracle-5.4 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-raspi 20.10 groovy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-raspi-5.4 20.10 groovy Not in release
20.04 LTS focal 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 20.10 groovy Not in release
20.04 LTS focal
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-raspi2-5.3 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-riscv 20.10 groovy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-snapdragon 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release

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Notes

sbeattie

fix needs typo correction from lkml link in refs

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

References

Related Ubuntu Security Notices (USN)

    • USN-4679-1
    • Linux kernel vulnerabilities
    • 6 January 2021
    • USN-4680-1
    • Linux kernel vulnerabilities
    • 6 January 2021
    • USN-4708-1
    • Linux kernel vulnerabilities
    • 28 January 2021
    • USN-4751-1
    • Linux kernel vulnerabilities
    • 25 February 2021

Other references