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
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Piotnet | Piotnet Forms | ≤ 2.1.40 | — |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
GitHub 1 repository
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xShadow-Here/CVE-2026-4883 ★ 0 · Jun 4, 2026
Piotnet Forms Pro <= 2.1.40 - Unauthenticated Arbitrary File Upload → RCE
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Automated scanner template
A ready-made Nuclei template detects this vulnerability automatically. Vulnerabilities with public scanner templates are typically probed across the internet soon after the template appears — exposed systems should be patched first.
- Piotnet Forms Pro <= 2.1.40 - Unauthenticated Arbitrary File Upload RCE http/cves/2026/CVE-2026-4883.yaml
Source: projectdiscovery/nuclei-templates (MIT) — updated daily. Only links are listed.