# CVE-2021-43816: containerd: containerd is an open source container runtime

CVE-2021-43816 is fixed in 2 products on 1 platform, first by containerd 1.5.9-0ubuntu1~18.04.1, released January 5, 2022. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2021-43816
- Priority: Urgent
- CVSS: 9.1 (critical)
- EPSS: 0.0181
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jan 5, 2022

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | containerd Debian 12.15 (bookworm) | 1.5.9~ds1-1 | [DEBIAN-CVE-2021-43816](https://patchblox.com/security/data/fix/linux/debian-cve-2021-43816.md) | Jan 5, 2022 |
| Linux | containerd Debian 13.5 (trixie) | 1.5.9~ds1-1 | [DEBIAN-CVE-2021-43816](https://patchblox.com/security/data/fix/linux/debian-cve-2021-43816.md) | Jan 5, 2022 |
| Linux | containerd Debian 14 | 1.5.9~ds1-1 | [DEBIAN-CVE-2021-43816](https://patchblox.com/security/data/fix/linux/debian-cve-2021-43816.md) | Jan 5, 2022 |
| Linux | containerd Ubuntu 18.04.6 LTS (bionic) | 1.5.9-0ubuntu1~18.04.1 | [containerd 1.5.9-0ubuntu1~18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-containerd-1.5.9-0ubuntu1-18.04.1.md) | Jan 5, 2022 |
| Linux | containerd Ubuntu 20.04 LTS (focal) | 1.5.9-0ubuntu1~20.04.4 | [containerd 1.5.9-0ubuntu1~20.04.4](https://patchblox.com/security/data/fix/linux/ubuntu-focal-containerd-1.5.9-0ubuntu1-20.04.4.md) | Mar 1, 2022 |
| Linux | containerd Ubuntu 22.04.1 LTS (jammy) | 1.5.9-0ubuntu1 | [containerd 1.5.9-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-containerd-1.5.9-0ubuntu1.md) | Jan 5, 2022 |
| Linux | golang-github-containerd-containerd-dev Ubuntu 18.04.6 LTS (bionic) | 1.5.9-0ubuntu1~18.04.1 | [golang-github-containerd-containerd-dev 1.5.9-0ubuntu1~18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-golang-github-containerd-containerd-dev-1.5.9-0ubuntu1-18.04.1.md) | Jan 5, 2022 |
| Linux | golang-github-containerd-containerd-dev Ubuntu 20.04 LTS (focal) | 1.5.9-0ubuntu1~20.04.4 | [golang-github-containerd-containerd-dev 1.5.9-0ubuntu1~20.04.4](https://patchblox.com/security/data/fix/linux/ubuntu-focal-golang-github-containerd-containerd-dev-1.5.9-0ubuntu1-20.04.4.md) | Mar 1, 2022 |
| Linux | golang-github-containerd-containerd-dev Ubuntu 22.04.1 LTS (jammy) | 1.5.9-0ubuntu1 | [golang-github-containerd-containerd-dev 1.5.9-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-golang-github-containerd-containerd-dev-1.5.9-0ubuntu1.md) | Jan 5, 2022 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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