The nfs_can_extend_write function in fs/nfs/write.c in the Linux kernel before 3.13.3 relies on a write delegation to extend a write operation without a certain up-to-date verification, which allows local users to obtain sensitive information from kernel memory in opportunistic circumstances by writing to a file in an NFS filesystem and then reading the same file.
https://github.com/torvalds/linux/commit/263b4509ec4d47e0da3e753f85a39ea12d1eff24
https://bugzilla.redhat.com/show_bug.cgi?id=1066939
http://www.ubuntu.com/usn/USN-2140-1
http://www.ubuntu.com/usn/USN-2137-1
http://www.openwall.com/lists/oss-security/2014/02/20/16
http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.13.3