Thomas Biege discovered that fusermount in FUSE before 2.4.1, if installed
setuid root, allows local users to corrupt /etc/mtab and possibly modify mount
options by performing a mount over a directory whose name contains certain
special characters
Successful exploitation could result in a denial of service if mount options
become unusable. An attacker can also exploit this issue to add arbitrary mount
points that could grant the attacker read and possibly write access to
otherwise restricted or privileged mount points. Other attacks are also
possible.
For the testing distribution (etch) this is fixed in version 2.3.0-4.2etch1
For the unstable distribution (sid) this is fixed in version 2.4.1-0.1
This upgrade is recommended if you use fuse.
If you have the secure testing lines in your sources.list, you can update by running this command as root:
apt-get update && apt-get upgrade
To use the Debian testing security archive, add the following lines to your /etc/apt/sources.list:
deb http://secure-testing-mirrors.debian.net/debian-secure-testing etch-proposed-updates/security-updates main contrib non-free
deb-src http://secure-testing-mirrors.debian.net/debian-secure-testing etch-proposed-updates/security-updates main contrib non-free
