Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linuxfoundation | Containerd | >= 1.5.1, < 1.5.9 |
| Fedoraproject | Fedora | 34 |
Related Weaknesses (CWE)
References
- https://github.com/containerd/containerd/commit/a731039238c62be081eb8c31525b9884PatchThird Party Advisory
- https://github.com/containerd/containerd/issues/6194ExploitIssue TrackingThird Party Advisory
- https://github.com/containerd/containerd/security/advisories/GHSA-mvff-h3cj-wj9cThird Party Advisory
- https://github.com/dweomer/containerd/commit/f7f08f0e34fb97392b0d382e58916d68651PatchThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://github.com/containerd/containerd/commit/a731039238c62be081eb8c31525b9884PatchThird Party Advisory
- https://github.com/containerd/containerd/issues/6194ExploitIssue TrackingThird Party Advisory
- https://github.com/containerd/containerd/security/advisories/GHSA-mvff-h3cj-wj9cThird Party Advisory
- https://github.com/dweomer/containerd/commit/f7f08f0e34fb97392b0d382e58916d68651PatchThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
FAQ
What is CVE-2021-43816?
CVE-2021-43816 is a vulnerability with a CVSS score of 8.0 (HIGH). 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 runtim...
How severe is CVE-2021-43816?
CVE-2021-43816 has been rated HIGH with a CVSS base score of 8.0/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-43816?
Check the references section above for vendor advisories and patch information. Affected products include: Linuxfoundation Containerd, Fedoraproject Fedora.