The Backend subcomponent in TYPO3 4.0.13 and earlier, 4.1.x before 4.1.13, 4.2.x before 4.2.10, and 4.3.x before 4.3beta2 allows remote authenticated users to determine an encryption key via crafted input to a tt_content form element.
https://exchange.xforce.ibmcloud.com/vulnerabilities/53917
http://www.vupen.com/english/advisories/2009/3009
http://www.securityfocus.com/bid/36801
http://typo3.org/teams/security/security-bulletins/typo3-sa-2009-016