A malicious source package could write files outside the unpack directory.
Jakub Wilk and Raphael Hertzog discovered that dpkg-source did not correctly handle certain paths and symlinks when unpacking source-format version 3.0 packages. If a user or an automated system were tricked into unpacking a specially crafted source package, a remote attacker could modify files outside the target unpack directory, leading to a denial of service or potentially gaining access to the system.
6 January 2011
A security issue affects these releases of Ubuntu and its derivatives:
A malicious source package could write files outside the unpack directory.
Jakub Wilk and Raphael Hertzog discovered that dpkg-source did not correctly handle certain paths and symlinks when unpacking source-format version 3.0 packages. If a user or an automated system were tricked into unpacking a specially crafted source package, a remote attacker could modify files outside the target unpack directory, leading to a denial of service or potentially gaining access to the system.
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
In general, a standard system update will make all the necessary changes.