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CVE-2021-43816

8.0 · HIGH

containerd is an open source container runtime.

Published Jan 5, 2022CWE-281EPSS 1.68%

Overview

CVE-2021-43816 is a high-severity vulnerability. It was published on January 5, 2022 and has a CVSS 3.1 base score of 8.0 (HIGH).

This vulnerability has a CVSS 3.1 base score of 8.0, rated HIGH. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

Technical description

containerd is an open source container runtime. On installations using SELinux, such as EL8 (CentOS, RHEL), Fedora, or SUSE MicroOS, with containerd since v1.5.0-beta.0 as the backing container runtime interface (CRI), an unprivileged pod scheduled to the node may bind mount, via hostPath volume, any privileged, regular file on disk for complete read/write access (sans delete). Such is achieved by placing the in-container location of the hostPath volume mount at either `/etc/hosts`, `/etc/hostname`, or `/etc/resolv.conf`. These locations are being relabeled indiscriminately to match the container process-label which effectively elevates permissions for savvy containers that would not normally be able to access privileged host files. This issue has been resolved in version 1.5.9. Users are advised to upgrade as soon as possible.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

GitHubgithub.com/containerd/containerd/commit/a731039238c62be081eb8c31525b988415745eeaGitHubgithub.com/containerd/containerd/issues/6194GitHubgithub.com/containerd/containerd/security/advisories/GHSA-mvff-h3cj-wj9cGitHubgithub.com/dweomer/containerd/commit/f7f08f0e34fb97392b0d382e58916d6865100299Reflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GD5GH7NMK5VJMA2Y5CYB5O5GTPYMWMLX/Reflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MPDIZMI7ZPERSZE2XO265UCK5IWM7CID/GitHubgithub.com/containerd/containerd/commit/a731039238c62be081eb8c31525b988415745eeaGitHubgithub.com/containerd/containerd/issues/6194GitHubgithub.com/containerd/containerd/security/advisories/GHSA-mvff-h3cj-wj9cGitHubgithub.com/dweomer/containerd/commit/f7f08f0e34fb97392b0d382e58916d6865100299

How CyberStrike helps

Frequently asked questions

What is CVE-2021-43816?

CVE-2021-43816 is a high-severity vulnerability. It was published on January 5, 2022 and has a CVSS 3.1 base score of 8.0 (HIGH).

How severe is CVE-2021-43816?

This vulnerability has a CVSS 3.1 base score of 8.0, rated HIGH. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2021-43816?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-43816?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-43816 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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