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error code from gpgv, which causes apt to treat a repository as valid even when it has been signed with a key that has been revoked or expired, which might allow remote attackers to trick apt into installing malicious repositories.

The parse-get function in utils.c for apt-www-proxy 0.1 allows remote attackers to cause a denial of service (crash) via an empty HTTP request, which causes a null dereference.