Cross-site scripting (XSS) vulnerability in fe_adminlib.inc in TYPO3 4.0.x before 4.0.9, 4.1.x before 4.1.7, and 4.2.x before 4.2.1, as used in extensions such as (1) direct_mail_subscription, (2) feuser_admin, and (3) kb_md5fepw, allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.

TYPO3 4.0.x before 4.0.9, 4.1.x before 4.1.7, and 4.2.x before 4.2.1, uses an insufficiently restrictive default fileDenyPattern for Apache, which allows remote attackers to bypass security restrictions and upload configuration files such as .htaccess, or conduct file upload attacks using multiple extensions.