masqmail before 0.2.18 allows local users to overwrite arbitrary files via a symlink attack on a log file.
https://exchange.xforce.ibmcloud.com/vulnerabilities/22347
http://www.vupen.com/english/advisories/2005/1807
http://www.securityfocus.com/bid/14890
http://www.osvdb.org/displayvuln.php?osvdb_id=19584
http://www.mandriva.com/security/advisories?name=MDKSA-2005:168
http://www.debian.org/security/2005/dsa-848