TYPO3 Improper Neutralization of Input During Web Page Generation (Cross-site Scripting) Vulnerability - CVE-2023-24814

TYPO3 is a free and open source Content Management Framework released under the GNU General Public License. In affected versions the TYPO3 core component codeGeneralUtility::getIndpEnv()/code uses the unfiltered server environment variable codePATH_INFO/code which allows attackers to inject malicious content. In combination with the TypoScript setting codeconfig.absRefPrefixauto/code attackers can inject malicious HTML code to pages that have not been rendered and cached yet. As a result injected values would be cached and delivered to other website visitors (persisted cross-site scripting). Individual code which relies on the resolved value of codeGeneralUtility::getIndpEnv(39SCRIPT_NAME39)/code and corresponding usages (as shown below) are vulnerable as well. Additional investigations confirmed that at least Apache web server deployments using CGI (FPM FCGI/FastCGI and similar) are affected. However there still might be the risk that other scenarios like nginx IIS or Apache/mod_php are vulnerable. The usage of server environment variable codePATH_INFO/code has been removed from corresponding processings in codeGeneralUtility::getIndpEnv()/code. Besides that the public property codeTypoScriptFrontendController::absRefPrefix/code is encoded for both being used as a URI component and for being used as a prefix in an HTML context. This mitigates the cross-site scripting vulnerability. Users are advised to update to TYPO3 versions 8.7.51 ELTS 9.5.40 ELTS 10.4.35 LTS 11.5.23 LTS and 12.2.0 which fix this problem. For users who are unable to patch in a timely manner the TypoScript setting codeconfig.absRefPrefix/code should at least be set to a static path value instead of using auto - e.g. codeconfig.absRefPrefix//code. This workaround strongdoes not fix all aspects of the vulnerability/strong and is just considered to be an intermediate mitigation to the most prominent manifestation.