CVE-2021-43816

Name: CVE-2021-43816
Creator: NVD / NIST
Published: 2022-01-05T19:15:08.717+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.1/10EPSS 1.69%

Last modified Jun 17, 2026

CVE-2021-43816 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. 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). EPSS estimates a 1.69% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

9.1/10

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

EPSS Probability

1.69%

74.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Linuxfoundation	Containerd	>= 1.5.1, < 1.5.9
Linuxfoundation	Containerd	1.5.0
Fedoraproject	Fedora	34
Fedoraproject	Fedora	35

References

https://github.com/containerd/containerd/commit/a731039238c62be081eb8c31525b988415745eeaPatch, Third Party Advisory
https://github.com/containerd/containerd/issues/6194Exploit, Issue Tracking, Third Party Advisory
https://github.com/containerd/containerd/security/advisories/GHSA-mvff-h3cj-wj9cThird Party Advisory
https://github.com/dweomer/containerd/commit/f7f08f0e34fb97392b0d382e58916d6865100299Patch, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GD5GH7NMK5VJMA2Y5CYB5O5GTPYMWMLX/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MPDIZMI7ZPERSZE2XO265UCK5IWM7CID/
https://github.com/containerd/containerd/commit/a731039238c62be081eb8c31525b988415745eeaPatch, Third Party Advisory
https://github.com/containerd/containerd/issues/6194Exploit, Issue Tracking, Third Party Advisory
https://github.com/containerd/containerd/security/advisories/GHSA-mvff-h3cj-wj9cThird Party Advisory
https://github.com/dweomer/containerd/commit/f7f08f0e34fb97392b0d382e58916d6865100299Patch, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GD5GH7NMK5VJMA2Y5CYB5O5GTPYMWMLX/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MPDIZMI7ZPERSZE2XO265UCK5IWM7CID/

Timeline

Published: Jan 5, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-43816?

How severe is CVE-2021-43816?

CVE-2021-43816 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 1.69% probability of exploitation in the next 30 days.

How do I fix CVE-2021-43816?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-43816?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST