Home

Description

The Fluent Forms Pro Add On Pack plugin for WordPress is vulnerable to Insufficient Verification of Data Authenticity in all versions up to, and including, 6.1.17. This is due to the PayPal IPN (Instant Payment Notification) verification being disabled by default (`disable_ipn_verification` defaults to `'yes'` in `PayPalSettings.php`). This makes it possible for unauthenticated attackers to send forged PayPal IPN notifications to the publicly accessible IPN endpoint, marking unpaid form submissions as "paid" and triggering post-payment automation (emails, access grants, digital product delivery).

PUBLISHED Reserved 2026-02-12 | Published 2026-02-27 | Updated 2026-02-27 | Assigner Wordfence




HIGH: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Problem types

CWE-345 Insufficient Verification of Data Authenticity

Product status

Default status
unaffected

* (semver)
affected

Timeline

2026-02-12:Vendor Notified
2026-02-26:Disclosed

Credits

Prickly Cactus finder

References

www.wordfence.com/...-da06-4b44-ba70-63065e664b0d?source=cve

fluentforms.com/docs/changelog/

cve.org (CVE-2026-2428)

nvd.nist.gov (CVE-2026-2428)

Download JSON