CGI::Session 4.03-1 allows local users to overwrite arbitrary files via a symlink attack on temporary files used by (1) Driver::File, (2) Driver::db_file, and possibly (3) Driver::sqlite.
https://exchange.xforce.ibmcloud.com/vulnerabilities/25285
http://www.vupen.com/english/advisories/2006/0946
http://www.securityfocus.com/bid/17177