TYPO3 is an open source PHP based web content management system. In TYPO3 from version 10.4.0, and before version 10.4.10, RSS widgets are susceptible to XML external entity processing. This vulnerability is reasonable, but is theoretical - it was not possible to actually reproduce the vulnerability with current PHP versions of supported and maintained system distributions. At least with libxml2 version 2.9, the processing of XML external entities is disabled per default - and cannot be exploited. Besides that, a valid backend user account is needed. Update to TYPO3 version 10.4.10 to fix the problem described.