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No exploitation reportedFix available

CVE-2021-21334

No exploitation reported by the sources we read.

  • Published2021-03-10
  • WeaknessCWE-668

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2021-03-1022:15CVE publishedNVD

Versions per branch

NVD · OSV
Fedoraproject fedora
BranchAffectedFixed in
33.x= 33no fix published
34.x= 34no fix published
Linuxfoundation containerd
BranchAffectedFixed in
1.4≥ 1.4.0, < 1.4.41.4.4
1.3< 1.3.101.3.10

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • containerdUbuntu:Pro:16.04:LTSall versions · no fixed version listed
  • containerdUbuntu:20.04:LTSall versions · fixed in 1.3.3-0ubuntu2.3
  • containerdUbuntu:18.04:LTSall versions · fixed in 1.5.2-0ubuntu1~18.04.2
  • containerdSUSE:Manager Server 4.0all versions · fixed in 1.4.4-5.32.1
  • containerdSUSE:Manager Retail Branch Server 4.0all versions · fixed in 1.4.4-5.32.1
  • containerdSUSE:Manager Proxy 4.0all versions · fixed in 1.4.4-5.32.1
  • containerdSUSE:Linux Enterprise Server for SAP Applications 15 SP1all versions · fixed in 1.4.4-5.32.1
  • containerdSUSE:Linux Enterprise Server for SAP Applications 15all versions · fixed in 1.4.4-5.32.1

88 more package ranges on OSV.dev

Full record on NVD

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CNACVSS 3.16.3known since 2026-10-23
  • NVDCVSS 3.16.3read 2026-10-23
  • NVDCVSS 2.04.3read 2026-10-23
  • CNAweakness (CWE)CWE-668known since 2026-10-23
  • FIRST EPSSEPSS score2.0 %2026-11-08
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryMODERATE2024-01-31

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
Published
2021-03-10
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-6g2q-w5j3-fwh4

Frequently asked questions

What is CVE-2021-21334?

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.

Is CVE-2021-21334 actively exploited?

Active exploitation of CVE-2021-21334 has not been confirmed. Its EPSS score was 2.0% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-21334?

CVE-2021-21334 has a CVSS v3 base score of 6.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N.

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