CVE-2020-26216: Cross-Site Scripting in TYPO3 Fluid

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2020-11-17 · updated 2026-06-17
Weakness: CWE-79

Description

TYPO3 Fluid before versions 2.0.8, 2.1.7, 2.2.4, 2.3.7, 2.4.4, 2.5.11 and 2.6.10 is vulnerable to Cross-Site Scripting. Three XSS vulnerabilities have been detected in Fluid: 1. TagBasedViewHelper allowed XSS through maliciously crafted additionalAttributes arrays by creating keys with attribute-closing quotes followed by HTML. When rendering such attributes, TagBuilder would not escape the keys. 2. ViewHelpers which used the CompileWithContentArgumentAndRenderStatic trait, and which declared escapeOutput = false, would receive the content argument in unescaped format. 3. Subclasses of AbstractConditionViewHelper would receive the then and else arguments in unescaped format. Update to versions 2.0.8, 2.1.7, 2.2.4, 2.3.7, 2.4.4, 2.5.11 or 2.6.10 of this typo3fluid/fluid package that fix the problem described. More details are available in the linked advisory.

Affected products

TYPO3 Fluid: before 2.0.8; from 2.1.0 before 2.1.7; from 2.2.0 before 2.2.4; from 2.3.0 before 2.3.7; from 2.4.0 before 2.4.4; from 2.5.0 before 2.5.11 — fixed in 2.0.8, 2.1.7, 2.2.4, 2.3.7, 2.4.4, 2.5.11

How to fix

Upgrade to a fixed version: TYPO3 Fluid 2.0.8, 2.1.7, 2.2.4, 2.3.7. Check the vendor advisory for mitigations.

References

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