Mandriva Linux Security Advisory – Umount allows local users to trigger a NULL dereference and application crash by invoking the program with a pathname for a USB pen drive that was mounted and then physically removed, which might allow the users to obtain sensitive information, including core file contents.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/54951/MDKSA-2007-053.txt
Source: https://packetstormsecurity.com/files/54951/Mandriva-Linux-Security-Advisory-2007.053.html