exmh 2.2 and earlier allows local users to overwrite arbitrary files via a symlink attack on the exmhErrorMsg temporary file.
https://exchange.xforce.ibmcloud.com/vulnerabilities/5829
http://www.linux-mandrake.com/en/security/2001/MDKSA-2001-015.php3
http://www.debian.org/security/2001/dsa-022
http://www.beedub.com/exmh/symlink.html
http://marc.info/?l=bugtraq&m=97958594330100&w=2
http://marc.info/?l=bugtraq&m=97846489313059&w=2
http://archives.neohapsis.com/archives/freebsd/2001-01/0543.html