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Fencer Intel
high 8.8

CVE-2021-20182 json

A privilege escalation flaw was found in openshift4/ose-docker-builder.

published 5y ago modified 4mo ago also EUVD-2021-7637

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 66%
public exploits
0
none known

Summary

A privilege escalation flaw was found in openshift4/ose-docker-builder. The build container runs with high privileges using a chrooted environment instead of runc. If an attacker can gain access to this build container, they can potentially utilize the raw devices of the underlying node, such as the network and storage devices, to at least escalate their privileges to that of the cluster admin. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Patch / fix

  • redhat openshift_container_platform 4.4.33, 4.5.30, 4.6.15

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-20182 updated cvss 8.8

openshift: builder allows read and write of block devices

  • Red Hat OpenShift Container Platform 4.4 openshift4/ose-cli v4.4.0-202101261542.p0, openshift4/ose-pod v4.4.0-202101261542.p0, openshift4/ose-etcd v4.4.0-202101261542.p0, openshift4/ose-tests v4.4.0-202101261542.p0, openshift4/ose-console v4.4.0-202101261542.p0, openshift4/ose-coredns v4.4.0-202101261542.p0, +76 more
    fixed: vendor fix RHSA-2021:0281
  • Red Hat OpenShift Container Platform 4.5 openshift4/ose-docker-builder v4.5.0-202101250544.p0
    fixed: vendor fix RHBA-2021:0231
  • Red Hat OpenShift Container Platform 4.6 openshift4/ose-cli v4.6.0-202101230113.p0, openshift4/ose-pod v4.6.0-202101230113.p0, openshift4/ose-etcd v4.6.0-202101230113.p0, openshift4/ose-tests v4.6.0-202101251550.p0, openshift4/ose-console v4.6.0-202101230113.p0, openshift4/ose-coredns v4.6.0-202101230113.p0, +120 more
    fixed: vendor fix RHBA-2021:0235
  • Red Hat OpenShift Container Platform 3.11 atomic-openshift, atomic-openshift-pod, atomic-openshift-node, atomic-openshift-tests, atomic-openshift-master, atomic-openshift-clients, +7 more Red Hat OpenShift Container Platform 4.5 openshift4/ose-cli v4.5.0-202101230441.p0, openshift4/ose-pod v4.5.0-202101230441.p0, openshift4/ose-etcd v4.5.0-202101230441.p0, openshift4/ose-tests v4.5.0-202101230441.p0, openshift4/ose-console v4.5.0-202101230441.p0, openshift4/ose-coredns v4.5.0-202101230441.p0, +75 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.15% chance of exploitation in the next 30 days, higher than 66% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.5 AV:N/AC:L/Au:S/C:P/I:P/A:P

Affected products

  • n/a openshift

Classification

Weakness
  • CWE-552 Files or Directories Accessible to External Parties

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.