CVE-2026-2428

HIGH EPSS 3.7%

Published Feb 27, 20264mo ago · Modified Jun 17, 20261w ago

7.5 CVSS 3.1

High

Published Feb 27, 2026 4mo ago

Last Modified Jun 17, 2026 1w ago

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).

CVSS Details

Base Score

7.5

Exploitability

3.9

Impact

3.6

Vector string

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

Attack Vector Network

Attack Complexity Low

Privileges Required None

User Interaction None

Scope Unchanged

Confidentiality None

Integrity High

Availability None

Threat Intelligence

EPSS Exploit Probability

3.7% percentile

Exploit & Patch Status

No Known Exploit

No Patch Available

Weaknesses 1

CWE-345

References 2

fluentforms.com https://fluentforms.com/docs/changelog/#2-toc-title
wordfence.com https://www.wordfence.com/threat-intel/vulnerabilities/id/e5c62e54-da06-4b44-ba70-63065e664b0d?source=cve

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.