reprepro 1.3.0 through 2.2.3 does not properly verify signatures when updating repositories, which allows remote attackers to construct and distribute an ostensibly valid Release.gpg file by signing it with an unknown key, related to the update command.
http://www.securityfocus.com/bid/25537
http://www.debian.org/security/2007/dsa-1394
http://secunia.com/advisories/27334
http://secunia.com/advisories/26678
http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=5%3Bfilename=interdiff%3Batt=1%3Bbug=440535