In the Linux kernel before 5.7.8, fs/nfsd/vfs.c (in the NFS server) can set incorrect permissions on new filesystem objects when the filesystem lacks ACL support, aka CID-22cf8419f131. This occurs because the current umask is not considered.
http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00007.html
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=962254
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.7.8
https://security.netapp.com/advisory/ntap-20200904-0003/
https://usn.ubuntu.com/4465-1/
https://usn.ubuntu.com/4483-1/