CVE intelligence and bounded remediation

CVE-2020-27777 — A flaw was found in the way RTAS handled memory accesses in userspace to kernel communication

High CVSS 7.2

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.

Severity
High
CVSS
7.2 (2.0)
Published
2020-12-15
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-862

Affected products

  • linux / linux_kernel
  • 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

Showing 6 representative product identities from 11 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Authorization bypass, IDOR, and cross-tenant access

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Map object and action authorization checks across API, UI, batch, import/export, and background-job paths.
  • Identify tenant, ownership, role, and policy boundaries for affected resources and administrative operations.
  • Use synthetic fixtures to compare intended access matrices without accessing another user's real data.

Remediate safely

  • Enforce server-side authorization at each resource access and state transition using the authenticated principal and trusted tenant context.
  • Scope data queries by tenant and ownership; treat client-supplied identifiers, roles, and policy claims as untrusted.
  • Add deny-by-default policy tests for horizontal and vertical access across every affected transport.

Authoritative sources

Complete CVE record and remediation plan

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