# CVE-2021-20198: Auth bypass in openshift/installer

> Remote attackers can execute arbitrary commands in containers during OpenShift installation due to anonymous authentication on the kubelet port.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 23 Feb 2021
- **Updated:** 3 Aug 2024

## What is CVE-2021-20198?

CVE-2021-20198 is a high-severity authentication bypass vulnerability in openshift/installer, published on 23 Feb 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2021-20198?

It affects 1 product.


Products: Redhat Openshift Installer.

## How do I fix CVE-2021-20198?

No fix has been published for CVE-2021-20198 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20198 being exploited?

There is no known exploitation of CVE-2021-20198 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20198 and fix it if it is affected.

What it is: CVE-2021-20198 is a high-severity authentication bypass vulnerability in openshift/installer, published on 23 Feb 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-20198 in the wild and no public exploit code.

Affected product: openshift/installer. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-20198/ (Markdown: https://insights.sbomify.com/CVE-2021-20198/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20198
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20198
- OSV: https://osv.dev/vulnerability/CVE-2021-20198

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-20198/
Summaries are generated and may contain mistakes; the official description above is the record.