Backend API configuration using Page TSconfig is vulnerable to arbitrary code execution and cross-site scripting. TSconfig fields of page properties in backend forms can be used to inject malicious sequences. Field tsconfig_includes is vulnerable to directory traversal leading to same scenarios as having direct access to TSconfig settings.
A valid backend user account having access to modify values for fields pages.TSconfig
and pages.tsconfig_includes
is needed in order to exploit this vulnerability.
github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/2019-06-25-4.yaml
github.com/TYPO3-CMS/core
github.com/TYPO3-CMS/core/commit/3a99a0877de6ad9cb39ba73146292b90e13294db
github.com/TYPO3-CMS/core/commit/822e62ec267fbe3c70a26f1c4f73f47fc615c930
typo3.org/security/advisory/typo3-core-sa-2019-019