Medium severity · published Dec 15, 2020
CVE-2020-27777
A flaw was found in the way RTAS handled memory accesses in userspace to kernel communication
6.7
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
High
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 41% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
before 4.14.204; 4.15 before 4.19.155; 4.20 before 5.4.75; 5.5 before 5.9.5 · source: NVD
EL
Enterprise Linux · Redhat
5.0; 6.0; 7.0; 8.0 · source: NVD
OC
Openshift Container Platform · Redhat
4.4; 4.5; 4.6 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-27777
CVE.org
https://www.cve.org/CVERecord?id=CVE-2020-27777
Issue Tracking
https://bugzilla.redhat.com/show_bug.cgi?id=1900844
Exploit
https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?h=next&id=bd59380c5ba4147dcbaad3e582b55ccfd120b764
Exploit
https://www.openwall.com/lists/oss-security/2020/10/09/1
Mailing List
https://www.openwall.com/lists/oss-security/2020/11/23/2
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