cvedb.io
CVE-2021-37334
CRITICAL · CVSS 9.8
EPSS exploitation probability: 0%
Published 2021-08-25T22:15:07.123 · Last modified 2026-06-17T04:00:22.747

Summary

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.

Affected products

umbraco — forms

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.