Auth bypass in Linux Kernel
CVE-2020-27777
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.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.7 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.005 (38.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 38.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.000
Affected products
- Linux Kernel
- Red Hat Enterprise Linux — versions 5.0, 6.0, 7.0
- Red Hat Openshift Container Platform — versions 4.4, 4.5, 4.6
- Kernel — versions kernel 5.10-rc1
Weakness classification (CWE)
Public proof-of-concept exploits
References
- bugzilla.redhat.com/show_bug.cgi (Patch, Third Party Advisory, Issue Tracking)
- www.openwall.com/lists/oss-security/2020/10/09/1 (Exploit, Patch, Mailing List, Third Party Advisory)
- www.openwall.com/lists/oss-security/2020/11/23/2 (Mailing List, Third Party Advisory)
- git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/ (Exploit, Patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2020-27777?
- CVE-2020-27777 is a medium-severity vulnerability in Linux Kernel, classified under Missing Authorization. CVSS score: 6.7/10. Published 2020-12-15.
- How severe is CVE-2020-27777?
- Medium severity. CVSS v3 base score is 6.7 out of 10.
- Is CVE-2020-27777 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.