CVE-2021-20198
No exploitation reported by the sources we read.
- Published2021-02-23
- Fixed in0.9.0-master.0.20210125200451-95101da940b0
- WeaknessCWE-306
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
A flaw was found in the OpenShift Installer before version v0.9.0-master.0.20210125200451-95101da940b0. During installation of OpenShift Container Platform 4 clusters, bootstrap nodes are provisioned with anonymous authentication enabled on kubelet port 10250. A remote attacker able to reach this port during installation can make unauthenticated `/exec` requests to execute arbitrary commands within running containers. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Timeline
dates in UTC- 2021-02-2318:15CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-20198?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-20198?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 0.9 | < 0.9.0-master.0.20210125200451-95101da940b0 | 0.9.0-master.0.20210125200451-95101da940b0 | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Distribution builds and vendor advisories
Packages from OSV.dev and products from the vendors' CSAF advisories.
version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.
Vendor advisories
Red Hat Security Advisory: OpenShift Container Platform 4.6.16 security and bug fix update
Fix
- Update Redhat openshift installer to 0.9.0-master.0.20210125200451-95101da940b0
- Vendor fix Red Hat Product Security RHSA-2021:0308 · 3 productsFor OpenShift Container Platform 4.6 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.openshift.com/container-platform/4.6/release_notes/ocp-4-6-r…
- Workaround from the vendor Red Hat Product Security RHSA-2021:0308 · 359 productsThis issue is mitigated by default on AWS, Azure, GCP and OpenStack as port 10250 is not remotely accessible on bootstrap nodes. For other IPI platforms, bootstrap nodes only exist during the installation window so the exposure is limited. For UPI installations, administrators should prevent remote…
Advisories and patches
- bugzilla.redhat.comPatch · Vendor Advisory
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
- NVDCVSS 3.18.1read 2026-10-23
- NVDCVSS 2.06.8read 2026-10-23
- CNAweakness (CWE)CWE-306read 2026-10-23
- FIRST EPSSEPSS score1.8 %2026-10-22
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- Published
- 2021-02-23
- Last Modified
- 2026-06-17
- NVD status
- Modified
Frequently asked questions
What is CVE-2021-20198?
Is CVE-2021-20198 actively exploited?
What is the CVSS score for CVE-2021-20198?
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Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.