CVE-2021-43816

Public Exploit
Improper Preservation of Permissions in containerd

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.

Category

8.0
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.15%
Vendor Advisory fedoraproject.org Vendor Advisory fedoraproject.org
Affected: containerd containerd
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2021-43816?
CVE-2021-43816 has been scored as a high severity vulnerability.
How to fix CVE-2021-43816?
To fix CVE-2021-43816, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-43816 being actively exploited in the wild?
It is possible that CVE-2021-43816 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-43816?
CVE-2021-43816 affects containerd containerd.
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