CVE-2020-26216: 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...

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.

Metrics

CVSS 3.1

6.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS Probability

1.03%

59.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Typo3	Fluid	< 2.0.8
Typo3	Fluid	>= 2.1.0, < 2.1.7
Typo3	Fluid	>= 2.2.0, < 2.2.4
Typo3	Fluid	>= 2.3.0, < 2.3.7
Typo3	Fluid	>= 2.4.0, < 2.4.4
Typo3	Fluid	>= 2.5.0, < 2.5.11
Typo3	Fluid	>= 2.6.0, < 2.6.10

References

https://github.com/TYPO3/Fluid/commit/f20db4e74cf9803c6cffca2ed2f03e1b0b89d0dcPatch, Third Party Advisory
https://github.com/TYPO3/Fluid/security/advisories/GHSA-hpjm-3ww5-6cpfExploit, Third Party Advisory
https://typo3.org/security/advisory/typo3-core-sa-2020-009Exploit, Vendor Advisory
https://github.com/TYPO3/Fluid/commit/f20db4e74cf9803c6cffca2ed2f03e1b0b89d0dcPatch, Third Party Advisory
https://github.com/TYPO3/Fluid/security/advisories/GHSA-hpjm-3ww5-6cpfExploit, Third Party Advisory
https://typo3.org/security/advisory/typo3-core-sa-2020-009Exploit, Vendor Advisory

Timeline

Published: Nov 17, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-26216?

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.

How severe is CVE-2020-26216?

CVE-2020-26216 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 1.03% probability of exploitation in the next 30 days.

How do I fix CVE-2020-26216?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.