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error code from gpgv, which causes apt to treat a repository as valid even when it has been signed with a key that has been revoked or expired, which might allow remote attackers to trick apt into installing malicious repositories.
AV:N/AC:L/Au:N/C:C/I:C/A:C
This vulnerability has a 4.48% probability of being exploited in the next 30 days, ranking higher than 91% of all scored CVEs.