Describe CVE-2015-6734.
What is CVE-2015-6734?
Cross-site scripting (XSS) vulnerability in contrib/cssgen.php in the GeSHi, as used in the SyntaxHighlight_GeSHi extension and MediaWiki before 1.23.10, 1.24.x before 1.24.3, and 1.25.x before 1.25.2, allows remote attackers to inject arbitrary web script or HTML via unspecified vectors..