The highlighting functionality in geshi.php in GeSHi before 1.0.8 allows remote attackers to cause a denial of service (infinite loop) via an XML sequence containing an opening delimiter without a closing delimiter, as demonstrated using "<".

The set_language_path function in geshi.php in Generic Syntax Highlighter (GeSHi) before 1.0.8.1 might allow remote attackers to conduct file inclusion attacks via crafted inputs that influence the default language path ($path variable). NOTE: this issue has been disputed by a vendor, stating that only a static value is used, so this is not a vulnerability in GeSHi. Separate CVE identifiers would be created for web applications that integrate GeSHi in a way that allows control of the default language path

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.