Missing input validation in the ar/tar implementations of APT before version 2.1.2 could result in denial of service when processing specially crafted deb files.
apt 0.8.16, 0.9.7, and possibly other versions does not properly handle InRelease files, which allows man-in-the-middle attackers to modify packages before installation via unknown vectors, possibly related to integrity checking and the use of third-party repositories.
Apt 0.8.16~exp5ubuntu13.x before 0.8.16~exp5ubuntu13.6, 0.8.16~exp12ubuntu10.x before 0.8.16~exp12ubuntu10.7, and 0.9.7.5ubuntu5.x before 0.9.7.5ubuntu5.2, as used in Ubuntu, uses world-readable permissions for /var/log/apt/term.log, which allows local users to obtain sensitive shell information by reading the log file.
apt-get in apt before 0.7.21 does not check for the correct error code from gpgv, which causes apt to treat a repository as valid even when it has been signed with a key that has been revoked or expired, which might allow remote attackers to trick apt into installing malicious repositories.