Exim security update

[Leo Famulari]

I just updated Exim from 4.86 to 4.86.2, fixing CVE-2016-1531 [0].

"All installations having Exim set-uid root and using 'perl_startup' are
vulnerable to a local privilege escalation. Any user who can start an
instance of Exim (and this is normally *any* user) can gain root
privileges. If you do not use 'perl_startup' you *should* be safe." [1]

According to upstream, the changes may break existing installations.
Please read their announcement [1] for more details.

[0]
http://seclists.org/oss-sec/2016/q1/501
https://bugzilla.redhat.com/show_bug.cgi?id=1314293
https://security-tracker.debian.org/tracker/CVE-2016-1531
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-1531

[1]
https://lists.exim.org/lurker/message/20160302.191005.a72d8433.en.html