Format string vulnerability in the dkim_exim_verify_finish function in src/dkim.c in Exim before 4.76 might allow remote attackers to execute arbitrary code or cause a denial of service (daemon crash) via format string specifiers in data used in DKIM logging, as demonstrated by an identity field containing a % (percent) character.
https://bugzilla.redhat.com/show_bug.cgi?id=702474
http://www.debian.org/security/2011/dsa-2232
http://secunia.com/advisories/51155
http://lists.opensuse.org/opensuse-security-announce/2011-05/msg00005.html
http://git.exim.org/exim.git/commit/337e3505b0e6cd4309db6bf6062b33fa56e06cf8