What is CVE-2020-26227?

CVE-2020-26227 is a medium-severity vulnerability in TYPO3, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2020-11-23.

How severe is CVE-2020-26227?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in TYPO3

CVE-2020-26227

TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 9.5.23 and 10.4.10 the system extension Fluid (typo3/cms-fluid) of the TYPO3 core is vulnerable to cross-site scripting passing user-controlled data as argument to Fluid view helpers. Update to TYPO3 versions 9.5.23 or 10.4.10 that fix the problem described.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2020-11-23 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.007 (52.2th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 52.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

TYPO3
TYPO3 Typo3.cms — versions >= 9.0.0, < 9.5.23, >= 10.0.0, < 10.4.10

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-vqqx-jw6p-q3rf (Exploit, Third Party Advisory)
typo3.org/security/advisory/typo3-core-sa-2020-010 (Exploit, Vendor Advisory)

Frequently asked questions

What is CVE-2020-26227?: CVE-2020-26227 is a medium-severity vulnerability in TYPO3, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2020-11-23.
How severe is CVE-2020-26227?: Medium severity. CVSS v3 base score is 6.1 out of 10.