More information about this security flaw is available in the following bug: https://bugzilla.redhat.com/show_bug.cgi?id=2353043 Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Singularity does not use containerd as a runtime to execute containers. runc or crun is used for OCI-mode execution - and as a binary that is provided via the Fedora package.