TYPO3 Cross-Site Request Forgery (CSRF) Vulnerability - CVE-2021-41113

TYPO3 is an open source PHP based web content management system released under the GNU GPL. It has been discovered that the new TYPO3 v11 feature that allows users to create and share deep links in the backend user interface is vulnerable to cross-site-request-forgery. The impact is the same as described in TYPO3-CORE-SA-2020-006 (CVE-2020-11069). However it is not limited to the same site context and does not require the attacker to be authenticated. In a worst case scenario the attacker could create a new admin user account to compromise the system. To successfully carry out an attack an attacker must trick his victim to access a compromised system. The victim must have an active session in the TYPO3 backend at that time. The following Same-Site cookie settings in GLOBALSTYPO3_CONF_VARSBEcookieSameSite are required for an attack to be successful: SameSitestrict: malicious evil.example.org invoking TYPO3 application at good.example.org and SameSitelax or none: malicious evil.com invoking TYPO3 application at example.org. Update your instance to TYPO3 version 11.5.0 which addresses the problem described.