CVE-2026-2888 json
Formidable Forms <= 6.28 - Unauthenticated Payment Amount Manipulation via 'item_meta' Parameter
published 7mo ago modified 4mo ago also EUVD-2026-11766
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 33%
- public exploits
- 0
- none known
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.
Is CVE-2026-2888 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 7mo ago
Exploit prediction
0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
Affected products
- strategy11team Formidable Forms – Contact Form Plugin, Survey, Quiz, Payment, Calculator Form & Custom Form Builder
Classification
- Weakness
-
- CWE-639 Authorization Bypass Through User-Controlled Key
- Technology feeds
References
- wordfence.com /threat-intel/vulnerabilities/id/b8be3b6e-a035-4e6f-ba2b-ce9e59ebf2e0?source=cve
- plugins.trac.wordpress.org /browser/formidable/tags/6.28/stripe/models/FrmStrpLiteAuth.php#L322
- plugins.trac.wordpress.org /browser/formidable/tags/6.28/stripe/models/FrmStrpLiteAuth.php#L402
- plugins.trac.wordpress.org /browser/formidable/tags/6.28/stripe/controllers/FrmStrpLiteHooksController.php#L88
- plugins.trac.wordpress.org /changeset?sfp_email=&sfph_mail=&reponame=&new=3480574%40formidable%2Ftrunk&old=3460198%40formidable%2Ftrunk&s
Sources
- CVE List CVE-2026-2888
- NVD CVE-2026-2888
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.