distcc before 2.16, when running on 64-bit platforms, does not interpret IP-based access control rules correctly, which could allow remote attackers to bypass intended restrictions.
https://exchange.xforce.ibmcloud.com/vulnerabilities/17581
https://euvd.enisa.europa.eu/vulnerability/EUVD-2004-0600
http://www.securityfocus.com/bid/11319