The Formidable Forms plugin for WordPress is vulnerable to unauthorized arbitrary plugin installation and activation due to a missing capability check on the screen_page() and can_install_addon_api() functions in versions up to, and including, 6.3. This makes it possible for authenticated attackers, with minimal permissions such as subscribers to retrieve a valid token from the welcome page, and then subsequently install and activate arbitrary plugins onto the site utilizing that key. This can easily be leveraged by attackers to achieve remote code execution as they simply need to install another plugin with a vulnerability or functionality that will aid in further exploitation.
CVE-2023-2877 is a medium severity with CVSS 6.5 Remote Code Execution issue affecting the Plugin Formidable Forms – WordPress Form Builder for Contact Forms, Calculators, Quizzes & More. It affects Versions before 6.3.1 and is fixed in 6.3.1.
Use the related hub and response guides to connect this CVE-2023-2877 report with patch validation, scanner checks, and site hardening work.
Open the grouped hub for related CVEs, affected ranges, severity mix, and patch coverage.
Check access, XML-RPC exposure, backup readiness, and monitoring after patching.
Use containment, evidence capture, remediation, and validation steps when exploit risk is high.
CVE-2023-2877 is tracked for the Plugin Formidable Forms – WordPress Form Builder for Contact Forms, Calculators, Quizzes & More as medium severity with CVSS 6.5. The affected range is Versions before 6.3.1. Update Formidable Forms – WordPress Form Builder for Contact Forms, Calculators, Quizzes & More to 6.3.1 or newer where that version is compatible with the site.
Search engines and operators need more than a title. This page exposes the identifier, affected range, patch evidence, and source coverage that make the vulnerability actionable.
This report has a CVE identifier, which makes it suitable for focused search and vulnerability triage workflows.
Affected version data gives operators a concrete comparison point against installed WordPress software.
A fixed version is present, so the page can answer update and remediation intent directly.
External references are available for source validation, advisory review, and incident notes.
Use these checks when converting this record into a patch ticket, incident note, or risk acceptance decision.
Inventory the installed Plugin package and compare its version with Versions before 6.3.1.
Confirm Formidable Forms – WordPress Form Builder for Contact Forms, Calculators, Quizzes & More is updated to 6.3.1 or newer.
Review references and CVSS vector details for exploitability, authentication requirements, and exposure path.
After patching, re-run vulnerability monitoring and keep the related plugin or theme hub under review for follow-up CVEs.
| Software Type | Plugin |
|---|---|
| Software Slug |
formidable
View on wordpress.org
|
| CVE | CVE-2023-2877 |
| Patched Versions |
6.3.1
|
| Affected Versions |
Versions before 6.3.1
|
These internal links group the same WordPress plugin by CVE, issue type, severity, and patch status so operators and search engines can connect the full vulnerability cluster.
Formidable Forms <= 6.1.2 - Unauthenticated PHP Object Injection
Formidable Form Builder <= 4.02 - PHP Object Injection
Formidable Form Builder <= 4.09.04 - Unauthenticated Stored Cross-Site Scripting
Formidable Form Builder <= 1.07.11 - SQL Injection
Formidable Form Builder < 2.05.03 - Unauthenticated Stored Cross-Site Scripting
Formidable Forms <= 6.28 - Missing Authorization to Unauthenticated Payment Integrity Bypass via PaymentIntent Reuse
Formidable Form Builder <= 5.5.6 - Cross-Site Request Forgery
Formidable Forms <= 6.7 - HTML Injection
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