A local root privilege escalation vulnerability was found in Exim, Debian"s default mail transfer agent, in configurations using the "perl_startup" option . To address the vulnerability, updated Exim versions clean the complete execution environment by default, affecting Exim and subprocesses such as transports calling other programs, and thus may break existing installations. New configuration options were introduced to adjust this behavior. More information can be found in the upstream advisory at https://www.exim.org/static/doc/CVE-2016-1531.txt