contrib/example.php in GeSHi before 1.0.7.3 allows remote attackers to read arbitrary files via the language field without a source field set.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2005-3080
http://www.securityfocus.com/bid/14903
http://sourceforge.net/project/shownotes.php?release_id=358285