CVE-2020-27777

medium
Published 2021-11-09 · Modified 2021-11-12
CVSS v3
CVSS v2
VIR risk
5.5

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.

Predictions

Exploit likelihood
20%
Patch ETA

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: alma — https://errata.almalinux.org/8/ALSA-2021-4356.html

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2020-27777

vendor Authored 2026-05-27

Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2020-27777.html

OS impact

OSVersionStatusFixed in
suse slesaffected
debian debianbookwormfixed5.9.6-1
debian debianbullseyefixed5.9.6-1
debian debianforkyfixed5.9.6-1
debian debiansidfixed5.9.6-1
debian debiantrixiefixed5.9.6-1

References

Verify integrity in audit chain (admin only). AS-IS.