Cross-Site Scripting in Content Preview
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
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | typo3/cms | >= 10.0.0, < 10.4.14, >= 11.0.0, < 11.1.1 | 10.4.14, 11.1.1 |
| Composer package | typo3/cms-backend | >= 10.0.0, < 10.4.14, >= 11.0.0, < 11.1.1 | 10.4.14, 11.1.1 |
| Composer package | typo3/cms-core | >= 10.0.0, < 10.4.14, >= 11.0.0, < 11.1.1 | 10.4.14, 11.1.1 |
References
- https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-fjh3-g8gq-9q92
- https://nvd.nist.gov/vuln/detail/CVE-2021-21340
- 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
- https://packagist.org/packages/typo3/cms-backend
- https://typo3.org/security/advisory/typo3-core-sa-2021-007
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N- Weakness (CWE)
CWE-79- Platform
- Composer
- Package
typo3/cms, typo3/cms-backend, typo3/cms-core- Disclosed
- 23.03.2021
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-fjh3-g8gq-9q92 - CC BY 4.0
Vulnerability history: typo3/cms-core
All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 128
- First → latest
- 09.2018 09.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 35
- Medium 84
- Low 8
Disclosures per year
- 2018: 2
- 2019: 0
- 2020: 13
- 2021: 15
- 2022: 34
- 2023: 3
- 2024: 38
- 2025: 8
- 2026: 15
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