Cross-site Scripting (XSS) in TYPO3 before 4.3.12, 4.4.x before 4.4.9, and 4.5.x before 4.5.4 allows remote attackers to inject arbitrary web script or HTML via the system extension recycler.
TYPO3 before 4.1.14, 4.2.x before 4.2.13, 4.3.x before 4.3.4 and 4.4.x before 4.4.1 is open to a session fixation attack which allows remote attackers to hijack a victim's session.
TYPO3 before 4.1.14, 4.2.x before 4.2.13, 4.3.x before 4.3.4 and 4.4.x before 4.4.1 contains an insecure default value of the variable fileDenyPattern which could allow remote attackers to execute arbitrary code on the backend.