I'm on Xubuntu 64 bit 14.04. When I had windows 7, I burnt a CD, it was like 4 months ago, now I need to open that CD in Xubuntu, since I no longer have windows.

sudo apt-get install libudf0
sudo chmod 777 /media
PS: I won't try ashish's solution unless someone confirms that it will work because mojo706 said that it didn't work.
▶ sudo mount -t udf /dev/sr0 /cdrom
mount: block device /dev/sr0 is write-protected, mounting read-only
mount: /dev/sr0: can't read superblock