Vulnerability · Published May 19, 2026 · Assigned by Wordfence
CVE-2026-4883Piotnet Forms <= 2.1.40 - Unauthenticated Arbitrary File Upload via Form File Upload
Critical 9.8
In plain English
A critical-severity unrestricted file upload in Piotnet Forms from Piotnet. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 3.1% (higher than 88% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei, public proof-of-concept code.
Official description
The Piotnet Forms plugin for WordPress is vulnerable to arbitrary file upload due to missing file type validation in the 'piotnetforms_ajax_form_builder' function in all versions up to, and including, 2.1.40. The plugin uses an incomplete extension blacklist that only blocks php, phpt, php5, php7, and exe extensions, while allowing dangerous extensions such as .phar or .phtml to be uploaded. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible. Note: The exploit can only be exploited if a file field is added to the form.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Piotnet | Piotnet Forms | 0 – through 2.1.40 |
Weakness: CWE-434 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H