CVE-2020-27777
kernel: powerpc: RTAS calls can be used to compromise kernel integrity
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · October 8, 2020
Updated · June 28, 2026
Description
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.
Statement
This issue is rated as having Moderate impact due to the required privileges and hardware dependencies.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
CVSS / CWE
CVSS 3.1 · 6.4CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
CWE-862 · Missing Authorization