An out of memory bounds write flaw (1 or 2 bytes of memory) in the Linux kernel NFS subsystem was found in the way users use mirroring (replication of files with NFS). A user, having access to the NFS mount, could potentially use this flaw to crash the system or escalate privileges on the system. https://nvd.nist.gov/vuln/detail/CVE-2021-4157
