Formidable Forms <= 6.0.1 - IP Spoofing via HTTP header

5.3
Reliance on Untrusted Inputs in a Security Decision
CVE CVE-2023-0816
CVSS 5.3 (Medium)
Publicly Published March 6, 2023
Last Updated January 22, 2024
Researcher Daniel Ruf

Description

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.

References

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Vulnerability Details for Formidable Forms – WordPress Form Builder for Contact Forms, Calculators, Quizzes & More

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

Recent vulnerabilities in Formidable Forms – WordPress Form Builder for Contact Forms, Calculators, Quizzes & More

# Title CVE ID CVSS Researchers Date
1 Formidable Forms <= 6.33.1 - Unauthenticated Stored Cross-Site Scripting via 'frm_user_id' Parameter CVE-2026-18331 7.2 daroo August 25, 2026
2 Formidable Forms <= 6.32.0 - Unauthenticated Payment Bypass CVE-2026-11361 5.3 Yaswanth Reddy Sunkara June 25, 2026
3 Formidable Forms <= 6.28 - Unauthenticated Payment Amount Manipulation via 'item_meta' Parameter CVE-2026-2888 5.3 Michael Iden (Mickhat) March 12, 2026
4 Formidable Forms <= 6.28 - Missing Authorization to Unauthenticated Payment Integrity Bypass via PaymentIntent Reuse CVE-2026-2890 7.5 Andrés Cruciani March 12, 2026
5 Formidable Forms – Contact Form Plugin, Survey, Quiz, Payment, Calculator Form & Custom Form Builder <= 6.16.1.2 - Reflected Cross-Site Scripting via Custom HTML Form Parameter CVE-2024-11188 6.1 mikemyers November 22, 2024
6 Formidable Forms – Contact Form Plugin, Survey, Quiz, Payment, Calculator Form & Custom Form Builder <= 6.14 - Authenticated (Admin+) Stored Cross-Site Scripting CVE-2024-9768 4.4 Krugov Artyom October 31, 2024
7 Formidable Forms <= 6.11.1 - Authenticated (Subscriber+) Stored Cross-Site Scripting CVE-2024-6725 4.9 zer0gh0st July 30, 2024
8 Formidable Forms <= 6.7.2 - Cross-Site Request Forgery to Stored Cross-Site Scripting CVE-2024-0660 6.1 Webbernaut January 26, 2024
9 Formidable Forms <= 6.7 - Authenticated (Administrator+) Stored Cross-Site Scripting CVE-2023-6842 4.4 drop January 8, 2024
10 Formidable Forms <= 6.7 - HTML Injection CVE-2023-6830 6.5 drop January 8, 2024

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