A vulnerability was recently discovered in the rpc.mountd daemon in the nfs-utils package for Linux, that allows a NFSv3 client to escalate the privileges assigned to it in the /etc/exports file at mount time. In particular, it allows the client to access any subdirectory or subtree of an exported directory, regardless of the set file permissions, and regardless of any 'root_squash' or 'all_squash' attributes that would normally be expected to apply to that client.

The nfs-utils package in SUSE Linux Enterprise Server 12 before and including version 1.3.0-34.18.1 and in SUSE Linux Enterprise Server 15 before and including version 2.1.1-6.10.2 the directory /var/lib/nfs is owned by statd:nogroup. This directory contains files owned and managed by root. If statd is compromised, it can therefore trick processes running with root privileges into creating/overwriting files anywhere on the system.

The nfs_addmntent function in support/nfs/nfs_mntent.c in the mount.nsf tool in nfs-utils before 1.2.4 attempts to append to the /etc/mtab file without first checking whether resource limits would interfere, which allows local users to corrupt this file via a process with a small RLIMIT_FSIZE value, a related issue to CVE-2011-1089.

The host_reliable_addrinfo function in support/export/hostname.c in nfs-utils before 1.2.4 does not properly use DNS to verify access to NFS exports, which allows remote attackers to mount filesystems by establishing crafted DNS A and PTR records.

rpc-gssd in nfs-utils before 1.2.8 performs reverse DNS resolution for server names during GSSAPI authentication, which might allow remote attackers to read otherwise-restricted files via DNS spoofing attacks.

Off-by-one error in the xlog function of mountd in the Linux NFS utils package (nfs-utils) before 1.0.4 allows remote attackers to cause a denial of service and possibly execute arbitrary code via certain RPC requests to mountd that do not contain newlines.