William Grant discovered that the dpkg-source component of dpkg, the low-level infrastructure for handling the installation and removal of Debian software packages, is vulnerable to path traversal attacks. A specially crafted Debian source package can lead to file modification outside of the destination directory when extracting the package content.
For the stable distribution (lenny), this problem has been fixed in version 1.14.29.
For the testing (squeeze) and unstable (sid) distribution this problem will be fixed soon.
We recommend that you upgrade your dpkg packages.