CVE-2021-37334

CRITICAL

9.8

CVSS Score

Published: August 25, 2021 at 09:16 PM UTC

Updated: June 17, 2026 at 04:00 AM UTC

1 product affected across 1 vendorForms

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Severity

CRITICAL9.8

Exploit prediction

EPSS 3%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Forms · Umbraco

95%

4.0.0 ≤ v < 4.4.96.0.0 ≤ v < 6.0.107.0.0 ≤ v < 7.0.77.1.0 ≤ v < 7.1.47.2.0 ≤ v < 7.2.17.3.0 ≤ v < 7.3.27.4.0 ≤ v < 7.4.37.5.0 ≤ v < 7.5.48.0.0 ≤ v < 8.0.28.1.0 ≤ v < 8.1.68.2.0 ≤ v < 8.2.38.3.0 ≤ v < 8.3.48.4.0 ≤ v < 8.4.48.5.0 ≤ v < 8.5.78.6.0 ≤ v < 8.6.28.7.0 ≤ v < 8.7.6

Affected range stops below 4.4.9, so it looks safe — our inference, not a vendor statement

Affected range stops below 6.0.10, so it looks safe — our inference, not a vendor statement

Affected range stops below 7.0.7, so it looks safe — our inference, not a vendor statement

Affected range stops below 7.1.4, so it looks safe — our inference, not a vendor statement

Affected range stops below 7.2.1, so it looks safe — our inference, not a vendor statement

Affected range stops below 7.3.2, so it looks safe — our inference, not a vendor statement

Affected range stops below 7.4.3, so it looks safe — our inference, not a vendor statement

Affected range stops below 7.5.4, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.0.2, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.1.6, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.2.3, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.3.4, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.4.4, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.5.7, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.6.2, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.7.6, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (2)

x_refsource_MISCPatchVendor Advisory

Source: [email protected]

https://umbraco.com/blog/security-advisory-20th-of-july-2021-patch-is-now-available/

x_refsource_MISCVendor Advisory

Source: [email protected]

https://umbraco.com/blog/security-advisory-security-patches-for-umbraco-forms-ready-on-july-20th-2021-at-7-am-utc/

CVSS

9.8CRITICAL[email protected]

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: HIGH
Integrity: HIGH
Availability: HIGH

Vector?

Quick Info

StatusMODIFIED

CWE

NVD-CWE-noinfo

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