CVE-2021-21334: environment variable leak
Impact
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
Patches
This vulnerability has been fixed in containerd 1.3.10 and containerd 1.4.4. Users should update to these versions as soon as they are released.
Workarounds
There are no known workarounds.
For more information
If you have any questions or comments about this advisory:
Open an issue Email us at security@containerd.io if you think you’ve found a security bug.
Other sources
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.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is CVE-2021-21334?
CVE-2021-21334 is a vulnerability in containerd that allows containers sharing the same image to receive incorrect environment variables.
What is the severity of CVE-2021-21334?
CVE-2021-21334 has a severity rating of 6.3, which is considered medium.
How can CVE-2021-21334 be exploited?
CVE-2021-21334 can be exploited by launching containers through containerd's CRI implementation that share the same image.
What is the affected software for CVE-2021-21334?
The affected software for CVE-2021-21334 includes containerd versions before 1.3.10 and versions between 1.4.0 and 1.4.4.
How can I fix CVE-2021-21334?
To fix CVE-2021-21334, update containerd to version 1.3.10 or upgrade to a version between 1.4.0 and 1.4.4.