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Vulnerability record · CVE-2021-21334 · published 10 March 2021

CVE-2021-21334: Linuxfoundation containerd exposure of resource to wrong sphere vulnerability

Linuxfoundation · Containerd

In containerd (an industry-standard container runtime) before versions 1.3.10 and 1.4.4, containers launched through containerd's CRI implementation (through Kubernetes, crictl, or any other pod/container client that uses the containerd CRI service) that share the same image may receive incorrect environment variables, including values that are defined for other containers. If the affected containers have different security contexts, this may allow sensitive information to be unintentionally shared. If you are not using containerd's CRI implementation (through one of the mechanisms described above), you are not vulnerable to this issue. If you are not launching multiple containers or Kubernetes pods from the same image which have different environment variables, you are not vulnerable to this issue. If you are not launching multiple containers or Kubernetes pods from the same image in rapid succession, you have reduced likelihood of being vulnerable to this issue This vulnerability has been fixed in containerd 1.3.10 and containerd 1.4.4. Users should update to these versions.

6.3 CVSS 3.1 Medium EPSS 2.0% · top 19.8% CWE-668 · Exposure of resource to wrong sphere
6.3CVSS 3.1 base score, v2 4.3
2.0%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
16References
17 Jun 2026Last modified by NVD

Description

In containerd (an industry-standard container runtime) before versions 1.3.10 and 1.4.4, containers launched through containerd's CRI implementation (through Kubernetes, crictl, or any other pod/container client that uses the containerd CRI service) that share the same image may receive incorrect environment variables, including values that are defined for other containers. If the affected containers have different security contexts, this may allow sensitive information to be unintentionally shared. If you are not using containerd's CRI implementation (through one of the mechanisms described above), you are not vulnerable to this issue. If you are not launching multiple containers or Kubernetes pods from the same image which have different environment variables, you are not vulnerable to this issue. If you are not launching multiple containers or Kubernetes pods from the same image in rapid succession, you have reduced likelihood of being vulnerable to this issue This vulnerability has been fixed in containerd 1.3.10 and containerd 1.4.4. Users should update to these versions.

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/containerd/containerd/commit/05f951a3781f4f2c1911b05e61c160e9c30eaa8e PatchThird Party Advisory
https://github.com/containerd/containerd/releases/tag/v1.3.10 Release NotesThird Party Advisory
https://github.com/containerd/containerd/releases/tag/v1.4.4 Release NotesThird Party Advisory
https://github.com/containerd/containerd/security/advisories/GHSA-6g2q-w5j3-fwh4 Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KUE2Z2ZUWBHRU36ZGBD2YSJ
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QIBPKSX5IOWPM3ZPFB3JVLX
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VTXHA5JOWQRCCUZH7ZQBEYN
https://security.gentoo.org/glsa/202105-33 Third Party Advisory
https://github.com/containerd/containerd/commit/05f951a3781f4f2c1911b05e61c160e9c30eaa8e PatchThird Party Advisory
https://github.com/containerd/containerd/releases/tag/v1.3.10 Release NotesThird Party Advisory
https://github.com/containerd/containerd/releases/tag/v1.4.4 Release NotesThird Party Advisory
https://github.com/containerd/containerd/security/advisories/GHSA-6g2q-w5j3-fwh4 Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KUE2Z2ZUWBHRU36ZGBD2YSJ
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QIBPKSX5IOWPM3ZPFB3JVLX
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VTXHA5JOWQRCCUZH7ZQBEYN
https://security.gentoo.org/glsa/202105-33 Third Party Advisory

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Source: NIST National Vulnerability Database (record CVE-2021-21334), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.