FTP account upper directory
 

I have addded ftp user account on rhel4, but the problem is this ftp user is able to go to upper directory up to root directory. I have set the home dir for this user to be "/home/www/username".
chroot in vsftpd.conf is untouched so chroot is not enabled.

I don't what else to look. I would appreciate any help :)

because your home directory has the 'x' bit enabled for Other.
the home can be entered, but just read for Other and group :
#ls -l /
drwxr-xr-x 3 root root 1024 sep 7 01:48 home/
appear for me.
'x' for a diirectory is enable to enter it