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.

APT 0.7.x before 0.7.25 and 0.8.x before 0.8.16, when using the apt-key net-update to import keyrings, relies on GnuPG argument order and does not check GPG subkeys, which might allow remote attackers to install altered packages via a man-in-the-middle (MITM) attack. NOTE: this vulnerability exists because of an incomplete fix for CVE-2012-3587.

APT 0.7.x before 0.7.25 and 0.8.x before 0.8.16, when using the apt-key net-update to import keyrings, relies on GnuPG argument order and does not check GPG subkeys, which might allow remote attackers to install Trojan horse packages via a man-in-the-middle (MITM) attack.