A containerd security update has been released for Ubuntu Linux 18.04 LTS, 20.04 LTS, 20.10, and 21.04.

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Ubuntu Security Notice USN-5012-1
July 20, 2021

containerd vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 21.04
- Ubuntu 20.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS

Summary:

containerd could be made to overwrite file permissions.

Software Description:
- containerd: daemon to control runC

Details:

It was discovered that containerd incorrectly handled file permission
changes. If a user or automated system were tricked into launching a
specially crafted container image, a remote attacker could change
permissions on files on the host filesystem and possibly escalate
privileges.

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 21.04:
containerd 1.5.2-0ubuntu1~21.04.2

Ubuntu 20.10:
containerd 1.5.2-0ubuntu1~20.10.2

Ubuntu 20.04 LTS:
containerd 1.5.2-0ubuntu1~20.04.2

Ubuntu 18.04 LTS:
containerd 1.5.2-0ubuntu1~18.04.2

After a standard system update you need to restart containerd to make
all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-5012-1
CVE-2021-32760

Package Information:
  https://launchpad.net/ubuntu/+source/containerd/1.5.2-0ubuntu1~21.04.2
  https://launchpad.net/ubuntu/+source/containerd/1.5.2-0ubuntu1~20.10.2
  https://launchpad.net/ubuntu/+source/containerd/1.5.2-0ubuntu1~20.04.2
  https://launchpad.net/ubuntu/+source/containerd/1.5.2-0ubuntu1~18.04.2