Gravity Forms <= 3.0.2 — Unauthenticated Arbitrary File Upload via State/Chunk Hash Confusion

Overview

Advisory ID

CVE-2026-19513

Product

Gravity Forms gravityforms

Affected

≤3.0.2

Fixed in

3.0.3

Weakness

CWE-434 Arbitrary File Upload

Required access

No account needed

Published

Sep 1, 2026 · updated Nov 13, 2026

Credit

Alex Thomas, Wordfence Argus

Source

Wordfence Intelligence

The Gravity Forms plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 3.0.2. This is due to insufficient validation of multi-file upload chunk state in the GFAsyncUpload::upload() function, where public form state URL hashes can be reused as chunk continuation hashes and attacker-controlled temporary filenames are accepted before sanitization. This makes it possible for unauthenticated attackers, when a public form contains a File Upload field with Multiple Files enabled, to upload a valid PNG/PDF polyglot to an attacker-selected public .php or .html filename in the Gravity Forms temporary upload directory. This can lead to remote code execution on WordPress systems that use NGINX or other non .htaccess respecting web servers. NOTE: During installation and activation, the Gravity Forms plugin places a .htaccess file in this directory, which prevents this vulnerability from being exploited despite the PHP file being written to the temporary upload directory. In these cases where PHP execution is blocked, attacker-written HTML can result in stored same-origin cross-site scripting if a victim visits the generated file URL.

Not sure which version you run? Run a passive check — it reads public files only.

Remediation & mitigations

1. Update to version 3.0.3, or a newer patched version
2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.