CVE-2021-37334

Description

Umbraco Forms version 4.0.0 up to and including 8.7.5 and below are vulnerable to a security flaw that could lead to a remote code execution attack and/or arbitrary file deletion. A vulnerability occurs because validation of the file extension is performed after the file has been stored in a temporary directory. By default, files are stored within the application directory structure at %BASEDIR%/APP_DATA/TEMP/FileUploads/. Whilst access to this directory is restricted by the root web.config file, it is possible to override this restriction by uploading another specially crafted web.config file to the temporary directory. It is possible to exploit this flaw to upload a malicious script file to execute arbitrary code and system commands on the server.

9.8

CVSS

Severity: Critical

CVSS 3.1 •

CVSS 2.0 •

EPSS 1.20% Top 25%

Vendor Advisory umbraco.com Vendor Advisory umbraco.com

Affected: n/a n/a

References

Link	Tags
https://umbraco.com/blog/security-advisory-security-patches-for-umbraco-forms-ready-on-july-20th-2021-at-7-am-utc/	vendor advisory
https://umbraco.com/blog/security-advisory-20th-of-july-2021-patch-is-now-available/	patch vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-37334?: CVE-2021-37334 has been scored as a critical severity vulnerability.
How to fix CVE-2021-37334?: To fix CVE-2021-37334, 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-2021-37334 being actively exploited in the wild?: It is possible that CVE-2021-37334 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.

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