Unrestricted File Upload vulnerability in the fileDenyPattern in sysext/core/Classes/Core/SystemEnvironmentBuilder.php in TYPO3 7.6.0 to 7.6.21 and 8.0.0 to 8.7.4 allows remote authenticated users to upload files with a .pht extension and consequently execute arbitrary PHP code.

TYPO3 7.6.15 sends an http request to an index.php?loginProvider URI in cases with an https Referer, which allows remote attackers to obtain sensitive cleartext information by sniffing the network and reading the userident and username fields.