Multiple untrusted search path vulnerabilities in Portage before 2.1.4.5 include the current working directory in the Python search path, which allows local users to execute arbitrary code via a modified Python module that is loaded by the (1) ys-apps/portage, (2) net-mail/fetchmail, (3) app-editors/leo ebuilds, and other ebuilds.
https://exchange.xforce.ibmcloud.com/vulnerabilities/45792
http://www.securityfocus.com/bid/31670