Fluent Forms Pro Add On Pack <= 6.1.17 - Missing Authorization to Unauthenticated Payment Status modification

2026-02-26 14:33

Prickly Cactus

Strategic Overview

Status

Patched in 6.1.18

Affected PluginFluent Forms Pro Add On Pack

Affected Version<= 6.1.17

CVSS7.5High

CVECVE-2026-2428

View all Fluent Forms Pro Add On Pack vulnerabilities

Vulnerability Overview

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).

Technical Analysis

REMEDIATION: Update to version 6.1.18, or a newer patched version --- IDENTIFIER: CWE-345 (Insufficient Verification of Data Authenticity) The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.

External References

https://www.cve.org/CVERecord?id=CVE-2026-2428 https://www.wordfence.com/threat-intel/vulnerabilities/id/e5c62e54-da06-4b44-ba70-63065e664b0d

CVSS Vector

7.5

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityHigh
AvailabilityNone

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