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.
This vulnerability carries a CRITICAL severity rating with a CVSS v3.1 score of 9.8, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts confidentiality (data exposure), integrity (unauthorized modifications), and availability (service disruption) for affected systems. Impacting 1 product from umbraco organizations running these solutions should prioritize assessment and patching.
Reported in 2021, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.
2021-08-25T22:15:07.123
2024-11-21T06:14:58.420
Modified
CVSSv3.1: 9.8 (CRITICAL)
AV:N/AC:M/Au:N/C:C/I:C/A:C
8.6
10.0
| Type | Vendor | Product | Version/Range | Vulnerable? |
|---|---|---|---|---|
| Application | umbraco | forms | < 4.4.9 | Yes |
| Application | umbraco | forms | < 6.0.10 | Yes |
| Application | umbraco | forms | < 7.0.7 | Yes |
| Application | umbraco | forms | < 7.1.4 | Yes |
| Application | umbraco | forms | < 7.2.1 | Yes |
| Application | umbraco | forms | < 7.3.2 | Yes |
| Application | umbraco | forms | < 7.4.3 | Yes |
| Application | umbraco | forms | < 7.5.4 | Yes |
| Application | umbraco | forms | < 8.0.2 | Yes |
| Application | umbraco | forms | < 8.1.6 | Yes |
| Application | umbraco | forms | < 8.2.3 | Yes |
| Application | umbraco | forms | < 8.3.4 | Yes |
| Application | umbraco | forms | < 8.4.4 | Yes |
| Application | umbraco | forms | < 8.5.7 | Yes |
| Application | umbraco | forms | < 8.6.2 | Yes |
| Application | umbraco | forms | < 8.7.6 | Yes |
SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For umbraco's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.