CVE-2026-84434

Critical CVSS 9.8

Published 2026-09-19 · last changed 2026-09-19

The fix

We hold no Microsoft remediation data for CVE-2026-84434, which normally means it is not a Windows CVE. For non-Microsoft software the fix is the vendor's own updated release, and the affected versions are listed below.

What it is

The Gravity Forms plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 3.1.0.4 via the upload_file function. This is due to a mismatch between the field validation pipeline and the file persistence pipeline, where hidden file upload fields bypass extension validation and a rejected file's intact upload state is later passed to upload_file() without re-validation. This makes it possible for unauthenticated attackers to upload files that may be executable, which makes remote code execution possible. Exploitation requires the targeted form to contain a File Upload field with its Visibility set to 'Hidden'; the vulnerability is reachable by unauthenticated attackers on any publicly accessible form meeting this condition.

Sources

NVD record for CVE-2026-84434

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H