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).
