CVE-2020-15099

In TYPO3 CMS greater than or equal to 9.0.0 and less than 9.5.20, and
greater than or equal to 10.0.0 and less than 10.4.6, in a case where an
attacker manages to generate a valid cryptographic message authentication
code (HMAC-SHA1) - either by using a different existing vulnerability or in
case the internal encryptionKey was exposed - it is possible to retrieve
arbitrary files of a TYPO3 installation. This includes the possibility to
fetch typo3conf/LocalConfiguration.php, which again contains the
encryptionKey as well as credentials of the database management system
being used. In case a database server is directly accessible either via
internet or in a shared hosting network, this allows the ability to
completely retrieve, manipulate or delete database contents. This includes
creating an administration user account - which can be used to trigger
remote code execution by injecting custom extensions. This has been patched
in versions 9.5.20 and 10.4.6.