CVE-2020-27777

Name: CVE-2020-27777
Creator: NVD / NIST
Published: 2020-12-15T17:15:14.333+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.7/10EPSS 0.51%

Last modified Jun 17, 2026

CVE-2020-27777 is a medium-severity vulnerability rated 6.7/10 on the CVSS scale. 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.. EPSS estimates a 0.51% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

6.7/10

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.51%

39.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-862

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	< 4.14.204
Linux	Linux Kernel	>= 4.15, < 4.19.155
Linux	Linux Kernel	>= 4.20, < 5.4.75
Linux	Linux Kernel	>= 5.5, < 5.9.5
Redhat	Openshift Container Platform	4.4
Redhat	Openshift Container Platform	4.5
Redhat	Openshift Container Platform	4.6
Redhat	Enterprise Linux	5.0
Redhat	Enterprise Linux	6.0
Redhat	Enterprise Linux	7.0
Redhat	Enterprise Linux	8.0

References

https://bugzilla.redhat.com/show_bug.cgi?id=1900844Issue Tracking, Patch, Third Party Advisory
https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?h=next&id=bd59380c5ba4147dcbaad3e582b55ccfd120b764Exploit, Patch, Vendor Advisory
https://www.openwall.com/lists/oss-security/2020/10/09/1Exploit, Mailing List, Patch, Third Party Advisory
https://www.openwall.com/lists/oss-security/2020/11/23/2Mailing List, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1900844Issue Tracking, Patch, Third Party Advisory
https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?h=next&id=bd59380c5ba4147dcbaad3e582b55ccfd120b764Exploit, Patch, Vendor Advisory
https://www.openwall.com/lists/oss-security/2020/10/09/1Exploit, Mailing List, Patch, Third Party Advisory
https://www.openwall.com/lists/oss-security/2020/11/23/2Mailing List, Third Party Advisory

Timeline

Published: Dec 15, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-27777?

How severe is CVE-2020-27777?

CVE-2020-27777 has a CVSS score of 6.7/10 (MEDIUM severity). The EPSS model estimates a 0.51% probability of exploitation in the next 30 days.

How do I fix CVE-2020-27777?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-27777?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST