Formidable Forms <= 6.0.1 - IP Spoofing via HTTP header

Reliance on Untrusted Inputs in a Security Decision
CVE CVE-2023-0816
CVSS 5.3 (Medium)
Publicly Published March 6, 2023
Last Updated March 10, 2023
Researcher Daniel Ruf


The Formidable Forms plugin for WordPress is vulnerable to IP Spoofing in versions up to, and including, 6.0.1 due to a reliance on various untrusted headers (e.g., 'Client-Ip', 'CF-CONNECTING-IP', etc.) to retrieve the IP address of a client performing a form submission. This makes it possible for unauthenticated users to bypass the plugin's anti-spam protections.



1 affected software package

Software Type Plugin
Software Slug formidable (view on
Patched? Yes
Remediation Update to version 6.1, or a newer patched version
Affected Version
  • <= 6.0.1
Patched Version
  • 6.1

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