Problem

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.

References

• TYPO3-CORE-SA-2021-007

References

• GHSA-fjh3-g8gq-9q92
• https://packagist.org/packages/typo3/cms-backend
• https://nvd.nist.gov/vuln/detail/CVE-2021-21340
• https://typo3.org/security/advisory/typo3-core-sa-2021-007
• https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2021-21340.yaml
• https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms/CVE-2021-21340.yaml