What the vulnerability does
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.
