APT before 1.0.9, when the Acquire::GzipIndexes option is enabled, does not validate checksums, which allows remote attackers to execute arbitrary code via a crafted package.

The apt-get download command in APT before 1.0.9 does not properly validate signatures for packages, which allows remote attackers to execute arbitrary code via a crafted package.

APT before 1.0.9 does not verify downloaded files if they have been modified as indicated using the If-Modified-Since header, which has unspecified impact and attack vectors.

The changelog command in Apt before 1.0.9.2 allows local users to write to arbitrary files via a symlink attack on the changelog file.

Buffer overflow in the HTTP transport code in apt-get in APT 1.0.1 and earlier allows man-in-the-middle attackers to cause a denial of service (crash) or possibly execute arbitrary code via a crafted URL.

APT before 1.0.4 does not properly validate source packages, which allows man-in-the-middle attackers to download and install Trojan horse packages by removing the Release signature.

The pkgAcqMetaClearSig::Failed method in apt-pkg/acquire-item.cc in Advanced Package Tool (APT) 0.8.11 through 0.8.15.10 and 0.8.16 before 0.8.16~exp13, when updating from repositories that use InRelease files, allows man-in-the-middle attackers to install arbitrary packages by preventing a user from downloading the new InRelease file, which leaves the original InRelease file active and makes it more difficult to detect that the Packages file is modified and unsigned.

methods/https.cc in apt before 0.8.11 accepts connections when the certificate host name fails validation and Verify-Host is enabled, which allows man-in-the-middle attackers to obtain repository credentials via unspecified vectors.

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.