- Component Type: TYPO3 CMS
- Subcomponent: Content Preview Renderer (ext:backend)
- Release Date: March 16, 2021
- Vulnerability Type: Cross-Site Scripting
- Affected Versions: 10.0.0-10.4.1, 11.0.0-11.1.0
- Severity: Medium
- Suggested CVSS: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N/E:F/RL:O/RC:C
- References: CVE-2021-21340, CWE-79
Problem Description
It has been discovered that database fields used as descriptionColumn are vulnerable to cross-site scripting when their content gets previewed in the page module. A valid backend user account is needed to exploit this vulnerability.
Solution
Update to TYPO3 versions 10.4.14, 11.1.1 that fix the problem described.
Credits
Thanks to Richie Lee who reported this issue and to TYPO3 framework merger Andreas Fernandez who fixed the issue.
General Advice
Follow the recommendations that are given in the TYPO3 Security Guide. Please subscribe to the typo3-announce mailing list.
General Note
All security related code changes are tagged so that you can easily look them up in our review system.