Description
TYPO3 is an open source PHP based web content management system. Starting in version 9.4.0 and prior to versions 9.5.42 ELTS, 10.4.39 ELTS, 11.5.30, and 12.4.4, in multi-site scenarios, enumerating the HTTP query parameters `id` and `L` allowed out-of-scope access to rendered content in the website frontend. For instance, this allowed visitors to access content of an internal site by adding handcrafted query parameters to the URL of a site that was publicly available. TYPO3 versions 9.5.42 ELTS, 10.4.39 ELTS, 11.5.30, 12.4.4 fix the problem.