main.C in maildrop 2.3.0 and earlier, when run by root with the -d option, uses the gid of root for execution of the .mailfilter file in a user's home directory, which allows local users to gain privileges via a crafted file.
https://exchange.xforce.ibmcloud.com/vulnerabilities/55980
https://bugzilla.redhat.com/show_bug.cgi?id=559681
http://www.debian.org/security/2010/dsa-1981
http://www.courier-mta.org/maildrop/changelog.html
http://securitytracker.com/id?1023515
http://secunia.com/advisories/38374
http://secunia.com/advisories/38367
http://marc.info/?l=oss-security&m=126468618017829&w=2
http://marc.info/?l=oss-security&m=126468551017070&w=2
http://marc.info/?l=oss-security&m=126468324913920&w=2