TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 9.5.23 and 10.4.10 user session identifiers were stored in cleartext - without processing with additional cryptographic hashing algorithms. This vulnerability cannot be exploited directly and occurs in combination with a chained attack - like for instance SQL injection in any other component of the system. Update to TYPO3 versions 9.5.23 or 10.4.10 that fix the problem described.

TYPO3 Fluid Engine (package `typo3fluid/fluid`) before versions 2.0.5, 2.1.4, 2.2.1, 2.3.5, 2.4.1, 2.5.5 or 2.6.1 is vulnerable to cross-site scripting when making use of the ternary conditional operator in templates like `{showFullName ? fullName : defaultValue}`. Updated versions of this package are bundled in following TYPO3 (`typo3/cms-core`) versions as well: TYPO3 v8.7.25 (using `typo3fluid/fluid` v2.5.4) and TYPO3 v9.5.6 (using `typo3fluid/fluid` v2.6.1).

In TYPO3 CMS greater than or equal to 9.0.0 and less than 9.5.20, and greater than or equal to 10.0.0 and less than 10.4.6, it has been discovered that an internal verification mechanism can be used to generate arbitrary checksums. This allows to inject arbitrary data having a valid cryptographic message authentication code (HMAC-SHA1) and can lead to various attack chains including potential privilege escalation, insecure deserialization & remote code execution. The overall severity of this vulnerability is high based on mentioned attack chains and the requirement of having a valid backend user session (authenticated). This has been patched in versions 9.5.20 and 10.4.6.

The typo3_forum extension before 1.2.1 for TYPO3 has Incorrect Access Control.

In TYPO3 CMS greater than or equal to 9.0.0 and less than 9.5.17 and greater than or equal to 10.0.0 and less than 10.4.2, calling unserialize() on malicious user-submitted content can lead to modification of dynamically-determined object attributes and result in triggering deletion of an arbitrary directory in the file system, if it is writable for the web server. It can also trigger message submission via email using the identity of the web site (mail relay). Another insecure deserialization vulnerability is required to actually exploit mentioned aspects. This has been fixed in 9.5.17 and 10.4.2.

In TYPO3 CMS 9.0.0 through 9.5.16 and 10.0.0 through 10.4.1, it has been discovered that the backend user interface and install tool are vulnerable to a same-site request forgery. A backend user can be tricked into interacting with a malicious resource an attacker previously managed to upload to the web server. Scripts are then executed with the privileges of the victims' user session. In a worst-case scenario, new admin users can be created which can directly be used by an attacker. The vulnerability is basically a cross-site request forgery (CSRF) triggered by a cross-site scripting vulnerability (XSS) - but happens on the same target host - thus, it's actually a same-site request forgery. Malicious payload such as HTML containing JavaScript might be provided by either an authenticated backend user or by a non-authenticated user using a third party extension, e.g. file upload in a contact form with knowing the target location. To be successful, the attacked victim requires an active…

In TYPO3 CMS 9.0.0 through 9.5.16 and 10.0.0 through 10.4.1, it has been discovered that backend user settings (in $BE_USER->uc) are vulnerable to insecure deserialization. In combination with vulnerabilities of third party components, this can lead to remote code execution. A valid backend user account is needed to exploit this vulnerability. This has been fixed in 9.5.17 and 10.4.2.

In TYPO3 CMS greater than or equal to 9.5.12 and less than 9.5.17, and greater than or equal to 10.2.0 and less than 10.4.2, it has been discovered that link tags generated by typolink functionality are vulnerable to cross-site scripting; properties being assigned as HTML attributes have not been parsed correctly. This has been fixed in 9.5.17 and 10.4.2.

In TYPO3 CMS greater than or equal to 9.0.0 and less than 9.5.17 and greater than or equal to 10.0.0 and less than 10.4.2, it has been discovered that HTML placeholder attributes containing data of other database records are vulnerable to cross-site scripting. A valid backend user account is needed to exploit this vulnerability. This has been fixed in 9.5.17 and 10.4.2.

In TYPO3 CMS versions 10.4.0 and 10.4.1, it has been discovered that time-based attacks can be used with the password reset functionality for backend users. This allows an attacker to mount user enumeration based on email addresses assigned to backend user accounts. This has been fixed in 10.4.2.