Kubernetes v1.19.15, v1.20.11 and v1.21.5 are now available in Rancher to address CVE-2021-25741 - Symlink Exchange Can Allow Host Filesystem Access.
Kubernetes v1.19.15 is now available for Rancher versions v2.5.0+
Kubernetes v1.20.11 is now available for Rancher versions v2.5.6+
Kubernetes v1.21.5 is now available for Rancher versions v2.6.0+
Note: If you are an air gapped user, please review the documentation on how to get these versions