CVE-2021-21370

Name: CVE-2021-21370
Creator: NVD / NIST
Published: 2021-03-23T02:15:12.987+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.4/10EPSS 0.87%

Last modified Jun 17, 2026

CVE-2021-21370 is a medium-severity vulnerability rated 5.4/10 on the CVSS scale. TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 7.6.51, 8.7.40, 9.5.25, 10.4.14, 11.1.1 it has been discovered that content elements of type _menu_ are vulnerable to cross-site scripting when their referenced items get previewed in the page module. EPSS estimates a 0.87% chance of exploitation in the next 30 days.

Description

TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 7.6.51, 8.7.40, 9.5.25, 10.4.14, 11.1.1 it has been discovered that content elements of type _menu_ are vulnerable to cross-site scripting when their referenced items get previewed in the page module. A valid backend user account is needed to exploit this vulnerability. This is fixed in versions 7.6.51, 8.7.40, 9.5.25, 10.4.14, 11.1.1.

Metrics

CVSS 3.1

5.4/10

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

EPSS Probability

0.87%

54.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Typo3	Typo3	>= 7.0.0, < 7.6.51
Typo3	Typo3	>= 8.0.0, < 8.7.40
Typo3	Typo3	>= 9.0.0, < 9.5.25
Typo3	Typo3	>= 10.0.0, < 10.4.14
Typo3	Typo3	>= 11.0.0, < 11.1.1

References

https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-x7hc-x7fm-f7qhThird Party Advisory
https://packagist.org/packages/typo3/cms-backendRelease Notes, Third Party Advisory
https://typo3.org/security/advisory/typo3-core-sa-2021-008Vendor Advisory
https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-x7hc-x7fm-f7qhThird Party Advisory
https://packagist.org/packages/typo3/cms-backendRelease Notes, Third Party Advisory
https://typo3.org/security/advisory/typo3-core-sa-2021-008Vendor Advisory

Timeline

Published: Mar 23, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-21370?

How severe is CVE-2021-21370?

CVE-2021-21370 has a CVSS score of 5.4/10 (MEDIUM severity). The EPSS model estimates a 0.87% probability of exploitation in the next 30 days.

How do I fix CVE-2021-21370?

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.

Are you affected by CVE-2021-21370?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST