CVE-2026-4883: Piotnet Forms (WordPress plugin) · Unrestricted File Upload
Affects Piotnet Forms (WordPress plugin)Source CVE Database V5
Not known to be exploited · public detection template (Nuclei) · CVSS 9.8 Critical.
Data as of 30 Oct 2026, 06:59 UTC
- EPSS
- 3.0% chance of exploitation in 30 days – higher than 87% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 May 2026
Detectable: evidence found.
nuclei template: Piotnet Forms Pro <= 2.1.40 - Unauthenticated Arbitrary File Upload RCE
Weaponized: evidence found.
Public exploit code: GitHub proofs of concept
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), GitHub proofs of concept, the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| PiotnetPiotnet Forms | Affected
| Fixed in– |
AI-suggested
Until an official fix is released, administrators should consider removing or disabling file upload fields in Piotnet Forms or restricting access to forms that include file uploads. Monitoring for suspicious file uploads and applying web application firewall rules to block dangerous file types may provide temporary mitigation. Avoid relying solely on the plugin's built-in file type restrictions.
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.