CVE-2021-37334

Critical

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.

SeverityCritical
CVSS9.8
Exploit probability—
ProductUmbraco Forms
PublishedAug 25, 2021
First seenAug 25, 2021

How to fix

Update
  • umbraco forms4.4.9, 6.0.10, 7.0.7, 7.1.4, 7.2.1, 7.3.2, 7.4.3, 7.5.4, 8.0.2, 8.1.6, 8.2.3, 8.3.4, 8.4.4, 8.5.7, 8.6.2, 8.7.6 or later

Affected products

ProductAffected versionsFixed in
umbraco forms4.0.0 ≤ v < 4.4.9, 6.0.0 ≤ v < 6.0.10, 7.0.0 ≤ v < 7.0.7, 7.1.0 ≤ v < 7.1.4, 7.2.0 ≤ v < 7.2.1, 7.3.0 ≤ v < 7.3.2, 7.4.0 ≤ v < 7.4.3, 7.5.0 ≤ v < 7.5.4, 8.0.0 ≤ v < 8.0.2, 8.1.0 ≤ v < 8.1.6, 8.2.0 ≤ v < 8.2.3, 8.3.0 ≤ v < 8.3.4, 8.4.0 ≤ v < 8.4.4, 8.5.0 ≤ v < 8.5.7, 8.6.0 ≤ v < 8.6.2, 8.7.0 ≤ v < 8.7.64.4.9, 6.0.10, 7.0.7, 7.1.4, 7.2.1, 7.3.2, 7.4.3, 7.5.4, 8.0.2, 8.1.6, 8.2.3, 8.3.4, 8.4.4, 8.5.7, 8.6.2, 8.7.6

Check your version

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