Comment 4 for bug 304959

This also applies to /var/tmp/ and to /dev/shm/

Temporary storage directories such as /tmp and /dev/shm potentially provide storage space for malicious exe-
cutables. Although mount options options cannot prevent interpreted code stored there from getting executed
by a program in another partition, using certain mount options can be disruptive to malicious code.

CCE 14412-1, 14940-1, 14927-8

http://www.nsa.gov/ia/_files/os/redhat/rhel5-guide-i731.pdf
Section 2.2.1.3