Several remotely exploitable vulnerabilities have been discovered in the TYPO3 web content management framework. The Common Vulnerabilities and Exposures project identifies the following problems: CVE-2009-0255 Chris John Riley discovered that the TYPO3-wide used encryption key is generated with an insufficiently random seed resulting in low entropy which makes it easier for attackers to crack this key. CVE-2009-0256 Marcus Krause discovered that TYPO3 is not invalidating a supplied session on authentication which allows an attacker to take over a victims session via a session fixation attack. CVE-2009-0257 Multiple cross-site scripting vulnerabilities allow remote attackers to inject arbitrary web script or HTML via various arguments and user- supplied strings used in the indexed search system extension, adodb extension test scripts or the workspace module. CVE-2009-0258 Mads Olesen discovered a remote command injection vulnerability in the indexed search system extension which allows attackers to execute arbitrary code via a crafted file name which is passed unescaped to various system tools that extract file content for the indexing. Because of CVE-2009-0255, please make sure that besides installing this update, you also create a new encryption key after the installation. For the stable distribution these problems have been fixed in version 4.0.2+debian-7. For the unstable distribution these problems have been fixed in version 4.2.5-1. We recommend that you upgrade your TYPO3 packages.