Ubuntu Security Notice 1666-1 - It was discovered that Aptdaemon incorrectly validated PPA GPG keys when importing from a keyserver. If a remote attacker were able to perform a man-in-the-middle attack, this flaw could be exploited to install altered package repository GPG keys.
42c16fb115783c46c14f38bed8c9cbdf8ad2e0cc19ff88ef969a9f2f6594d0c1