Debian: DSA 121-1 Critical: xtell Buffer Overflow And Remote Threats

Several security related problems have been found in the xtell
package, a simple messaging client and server. In detail, these
problems contain several buffer overflows, a problem in connection
with symbolic links, unauthorized directory traversal when the path
contains "..". These problems could lead into an attacker being able
to execute arbitrary code on the server machine. The server runs with
nobody privileges by default, so this would be the account to be
exploited.

They have been corrected by backporting changes from a newer upstream
version by the Debian maintainer for xtell. These problems are fixed
in version 1.91.1 in the stable distribution of Debian and in version
2.7 for the testing and unstable distribution of Debian.

We recommend that you upgrade your xtell packages immediately.

wget url
will fetch the file for you
dpkg -i file.deb
will install the referenced file.

If you are using the apt-get package manager, use the line for
sources.list as given below:

apt-get up...