CVE-2026-4883 Details
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.
A vulnerability allowing arbitrary file upload has been identified in the Piotnet Forms plugin for WordPress, affecting all versions through 2.1.40. The issue arises from inadequate file type validation in the 'piotnetforms_ajax_form_builder' function. The plugin's extension blacklist only partially restricts certain file types, allowing potentially dangerous extensions like .phar and .phtml to be uploaded. This flaw could enable unauthenticated attackers to upload arbitrary files to the server, potentially leading to remote code execution, especially if a file field is included in the form.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed May 19, 2026CISA-ADP
Assessed May 19, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://piotnetforms.com | [email protected] | ProductVendor |
| https://www.wordfence.com/threat-intel/vulnerabilities/id/9bd9c9db-d279-4de2-b5e4-ac7d8c919f2a?source=cve | [email protected] | AdvisoryRemedy |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-434 | Unrestricted Upload of File with Dangerous Type | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Piotnet Forms | <= 2.1.40 (semver) |
CPE
Remediation
| |
Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 19, 2026 | New CVE Received | [email protected] |
Volerion