The Formidable Forms plugin for WordPress is vulnerable to an authorization bypass through user-controlled key in all versions up to, and including, 6.28. This is due to the `frm_strp_amount` AJAX handler (`update_intent_ajax`) overwriting the global `$_POST` data with attacker-controlled JSON input and then using those values to recalculate payment amounts via field shortcode resolution in `generate_false_entry()`. The handler relies on a nonce that is publicly exposed in the page's JavaScript (`frm_stripe_vars.nonce`), which provides CSRF protection but not authorization. This makes it possible for unauthenticated attackers to manipulate PaymentIntent amounts before payment completion on forms using dynamic pricing with field shortcodes, effectively paying a reduced amount for goods or services.
CVE-2026-2888 is a medium severity with CVSS 5.3 Authorization Bypass issue affecting the Plugin Formidable Forms – WordPress Form Builder for Contact Forms, Calculators, Quizzes & More. It affects Versions up to 6.28 and is fixed in 6.29.
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CVE-2026-2888 is tracked for the Plugin Formidable Forms – WordPress Form Builder for Contact Forms, Calculators, Quizzes & More as medium severity with CVSS 5.3. The affected range is Versions up to 6.28. Update Formidable Forms – WordPress Form Builder for Contact Forms, Calculators, Quizzes & More to 6.29 or newer where that version is compatible with the site.
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| Software Type | Plugin |
|---|---|
| Software Slug |
formidable
View on wordpress.org
|
| CVE | CVE-2026-2888 |
| Patched Versions |
6.29
|
| Affected Versions |
Versions up to 6.28
|
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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