How severe is CVE-2021-43816?

CVE-2021-43816 has a CVSS 3.x base score of 8.0, rated high severity. It is exploitable over network with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-43816 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43816?

CVE-2021-43816 primarily affects Linuxfoundation Containerd. In total, 13 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-43816?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-43816 published?

CVE-2021-43816 was published on 2022-01-05 and last updated on 2026-06-17.

CVE-2021-43816

CVE-2021-43816 is a high-severity vulnerability in Linuxfoundation Containerd with a CVSS 3.x base score of 8.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-281.

Key facts

Severity: High (CVSS 3.x base score 8.0)
CVSS v2: 6.0
EPSS exploit prediction: 2% (74th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-281
Affected product: Linuxfoundation Containerd
Published: 2022-01-05
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-43816?: 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.
How severe is CVE-2021-43816?: CVE-2021-43816 has a CVSS 3.x base score of 8.0, rated high severity. It is exploitable over network with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-43816 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43816?: CVE-2021-43816 primarily affects Linuxfoundation Containerd. In total, 13 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-43816?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-43816 published?: CVE-2021-43816 was published on 2022-01-05 and last updated on 2026-06-17.

References

Affected products (13)

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:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*

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