CVE-2021-43816
containerd is an open source container runtime.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.68%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 3.1
- 9.1 CRITICALCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
- EPSS
- 1.68% probability · 76th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-281
- Affected
- linuxfoundation/containerd · fedoraproject/fedora
- Source
- security-advisories@github.com
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/
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.