CVE-2026-2888

Summary

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.

Affected Software

VendorProductVersion RangeStatus
strategy11teamFormidable Forms – Contact Form Plugin, Survey, Quiz, Payment, Calculator Form & Custom Form Builder0 <= 6.28affected

Weaknesses

  • CWE-639: CWE-639 Authorization Bypass Through User-Controlled Key

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

References