CVE-2021-21357

Broken Access Control in Form Framework

Description

TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 8.7.40, 9.5.25, 10.4.14, 11.1.1 due to improper input validation, attackers can by-pass restrictions of predefined options and submit arbitrary data in the Form Designer backend module of the Form Framework. In the default configuration of the Form Framework this allows attackers to explicitly allow arbitrary mime-types for file uploads - however, default _fileDenyPattern_ successfully blocked files like _.htaccess_ or _malicious.php_. Besides that, attackers can persist those files in any writable directory of the corresponding TYPO3 installation. A valid backend user account with access to the form module is needed to exploit this vulnerability. This is fixed in versions 8.7.40, 9.5.25, 10.4.14, 11.1.1.

Category

8.3
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 1.12% Top 25%
Vendor Advisory typo3.org
Affected: TYPO3 TYPO3.CMS
Published at:
Updated at:

References

Link Tags
https://packagist.org/packages/typo3/cms-form third party advisory release notes
https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-3vg7-jw9m-pc3f third party advisory
https://typo3.org/security/advisory/typo3-core-sa-2021-003 vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-21357?
CVE-2021-21357 has been scored as a high severity vulnerability.
How to fix CVE-2021-21357?
To fix CVE-2021-21357, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-21357 being actively exploited in the wild?
It is possible that CVE-2021-21357 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~1% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-21357?
CVE-2021-21357 affects TYPO3 TYPO3.CMS.
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