Edit your /etc/fstab:
# vi /etc/fstab
change:
none /dev/shm tmpfs defaults,rw 0 0
to
none /dev/shm tmpfs defaults,nosuid,noexec,rw 0 0
Remount /dev/shm:
# mount -o remount /dev/shm
You can test it runnig a script on /dev/shm, if you get “permission denied” it is fine!