CVE 2018-1000028

Linux kernel version after commit bdcf0a423ea1 - 4.15-rc4+, 4.14.8+, 4.9.76+, 4.4.111+ contains a Incorrect Access Control vulnerability in NFS server (nfsd) that can result in remote users reading or writing files they should not be able to via NFS. This attack appear to be exploitable via NFS server must export a filesystem with the "rootsquash" options enabled. This vulnerability appears to have been fixed in after commit 1995266727fa.

See the CVE page on Mitre.org for more details.