CVE-2026-4883: critical vulnerability in Piotnet Forms
Piotnet Forms <= 2.1.40 - Unauthenticated Arbitrary File Upload via Form File Upload
Published
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85Vexday Risk Score
Patch now. It exploitation observed by VulnCheck and has a working public exploit.
ssvc Actcvss 9.8epss 3.1%
from disclosure to weapon16 days
Published on NVDMay 19
1st PoC+16d
VulnCheck+147d
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products
Piotnet · Piotnet Formspublic PoCs found — 2
githubgithub.com/xShadow-Here/CVE-2026-4883★ 0vulncheckvulncheck.com/xdb/a751041177b2unverified⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
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