CVE-2021-37334: Critical severity Umbraco Forms vulnerability
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%/APPDATA/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.
Affected Software
Event History
Frequently Asked Questions
What is CVE-2021-37334?
CVE-2021-37334 is a security vulnerability in Umbraco Forms version 4.0.0 up to and including 8.7.5 and below that could lead to a remote code execution attack and/or arbitrary file deletion.
How severe is CVE-2021-37334?
CVE-2021-37334 has a severity rating of 9.8, which is considered critical.
Which versions of Umbraco Forms are affected by CVE-2021-37334?
Umbraco Forms version 4.0.0 up to and including 8.7.5 and below are affected by CVE-2021-37334.
What is the impact of CVE-2021-37334?
CVE-2021-37334 could lead to a remote code execution attack and/or arbitrary file deletion.
How can I patch or fix CVE-2021-37334?
To patch or fix CVE-2021-37334, you should update Umbraco Forms to version 8.7.6 or later, which includes security patches to address the vulnerability.