Exim is a message transfer agent (MTA) designed to be a a highly configurable, drop-in replacement for sendmail.
Vulnerabilities have been discovered in Exim’s implementation of set-uid root and when using ‘perl_startup’. These vulnerabilities require a user account on the Exim server and a configuration that does lookups against files to which the user has edit access.
A local attacker could possibly execute arbitrary code with the privileges of the process, or escalate privileges.
There is no known workaround at this time.
All Exim users should upgrade to the latest version:
# emerge --sync # emerge --ask --oneshot --verbose ">=mail-mta/exim-4.87"