Vulnerability Details : CVE-2021-43816
Potential exploit
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.
Products affected by CVE-2021-43816
- cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
- cpe:2.3:a:linuxfoundation:containerd:*:*:*:*:*:*:*:*
- cpe:2.3:a:linuxfoundation:containerd:1.5.0:-:*:*:*:*:*:*
- cpe:2.3:a:linuxfoundation:containerd:1.5.0:beta0:*:*:*:*:*:*
- cpe:2.3:a:linuxfoundation:containerd:1.5.0:beta1:*:*:*:*:*:*
- cpe:2.3:a:linuxfoundation:containerd:1.5.0:beta2:*:*:*:*:*:*
- cpe:2.3:a:linuxfoundation:containerd:1.5.0:beta3:*:*:*:*:*:*
- cpe:2.3:a:linuxfoundation:containerd:1.5.0:beta4:*:*:*:*:*:*
- cpe:2.3:a:linuxfoundation:containerd:1.5.0:rc0:*:*:*:*:*:*
- cpe:2.3:a:linuxfoundation:containerd:1.5.0:rc1:*:*:*:*:*:*
- cpe:2.3:a:linuxfoundation:containerd:1.5.0:rc2:*:*:*:*:*:*
- cpe:2.3:a:linuxfoundation:containerd:1.5.0:rc3:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-43816
0.14%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 31 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-43816
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
|---|---|---|---|---|---|---|
|
6.0
|
MEDIUM | AV:N/AC:M/Au:S/C:P/I:P/A:P |
6.8
|
6.4
|
NIST | |
|
9.1
|
CRITICAL | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H |
2.3
|
6.0
|
NIST | |
|
8.0
|
HIGH | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H |
1.3
|
6.0
|
GitHub, Inc. |
CWE ids for CVE-2021-43816
-
The product does not preserve permissions or incorrectly preserves permissions when copying, restoring, or sharing objects, which can cause them to have less restrictive permissions than intended.Assigned by:
- nvd@nist.gov (Secondary)
- security-advisories@github.com (Primary)
References for CVE-2021-43816
-
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GD5GH7NMK5VJMA2Y5CYB5O5GTPYMWMLX/
[SECURITY] Fedora 34 Update: containerd-1.6.0~rc.2-3.fc34 - package-announce - Fedora Mailing-ListsMailing List;Third Party Advisory
-
https://github.com/dweomer/containerd/commit/f7f08f0e34fb97392b0d382e58916d6865100299
Revert "[cri] label etc files for selinux containers" · dweomer/containerd@f7f08f0 · GitHubPatch;Third Party Advisory
-
https://github.com/containerd/containerd/security/advisories/GHSA-mvff-h3cj-wj9c
containerd CRI plugin: Unprivileged pod using `hostPath` can side-step SELinux · Advisory · containerd/containerd · GitHubThird Party Advisory
-
https://github.com/containerd/containerd/commit/a731039238c62be081eb8c31525b988415745eea
[cri] label etc files for selinux containers · containerd/containerd@a731039 · GitHubPatch;Third Party Advisory
-
https://github.com/containerd/containerd/issues/6194
cri + selinux: /etc/hosts from hostPath mount getting relabeled · Issue #6194 · containerd/containerd · GitHubExploit;Issue Tracking;Third Party Advisory
-
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/MPDIZMI7ZPERSZE2XO265UCK5IWM7CID/
[SECURITY] Fedora 35 Update: containerd-1.6.0~rc.2-2.fc35 - package-announce - Fedora Mailing-ListsMailing List;Third Party Advisory
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