Cross-site scripting (XSS) vulnerability in the sr_feuser_register 1.4.0, 1.6.0, 2.2.1 to 2.2.7, 2.3.0 to 2.3.6, 2.4.0, and 2.5.0 to 2.5.9 extension for TYPO3 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.