typo3-src: cross-site scripting

Helmut Hummel of the typo3 security team discovered that typo3, a web content management system, is not properly sanitizing output of the exception handler. This allows an attacker to conduct cross-site scripting attacks if either third-party extensions are installed that do not sanitize this output on their own or in the presence of extensions using the extbase MVC framework which accept objects to controller actions.