Guillem Jover discovered that the changelog retrieval functionality in
apt-get used temporary files in an insecure way, allowing a local user
to cause arbitrary files to be overwritten.
This vulnerability is neutralized by the fs.protected_symlinks setting in
the Linux kernel, which is enabled by default in Debian 7 Wheezy and up.
For the stable distribution (wheezy), this problem has been fixed in
For the unstable distribution (sid), this problem has been fixed in
Its recommended that you upgrade your apt packages.