fs/nfs/nfs4client.c in the Linux kernel before 5.13.4 has incorrect connection-setup ordering, which allows operators of remote NFSv4 servers to cause a denial of service (hanging of mounts) by arranging for those servers to be unreachable during trunking detection. CREATE(Triage):(User=admin) CVE-2021-38199 (https://nvd.nist.gov/vuln/detail/CVE-2021-38199)