The TYPO3 extension ke_dompdf contains a version of the dompdf library including all files originally supplied with it. This includes an examples page, which contains different examples for HTML-entities rendered as a PDF. This page also allows users to enter their own HTML code into a text box to be rendered by the webserver using dompdf. dompdf also supports rendering of PHP files and the examples page also accepts PHP code tags, which are then executed and rendered into a PDF on the server. Since those files are not protected in the TYPO3 extension directory, anyone can access this URL and execute arbitrary PHP code on the system. This behavior was already fixed in the dompdf library, but the typo3 extension ke_dompdf supplies an old version of the library that still allows the execution of arbitrary PHP code. Versions 0.0.3 and below are affected.