What’s Vulnerable › Vulnerabilities

CVE-2026-4883: Piotnet Forms <= 2.1.40 - Unauthenticated Arbitrary File Upload via Form File Upload

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.1% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-05-19 · updated 2026-06-17
• Weakness: CWE-434

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

• piotnetdotcom Piotnet Forms: through 2.1.40

References

• https://piotnetforms.com
• https://www.wordfence.com/threat-intel/vulnerabilities/id/9bd9c9db-d279-4de2-b5e4-ac7d8c919f2a?source=cve

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