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

7.5
Insufficient Verification of Data Authenticity
CVE CVE-2026-2428
CVSS 7.5 (High)
Publicly Published February 26, 2026
Last Updated March 12, 2026
Researcher Prickly Cactus

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).

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Vulnerability Details for Fluent Forms Pro Add On Pack

Software Type Plugin
Software Slug fluentformpro
Patched? Yes
Remediation Update to version 6.1.18, or a newer patched version
Affected Version
  • <= 6.1.17
Patched Version
  • 6.1.18

Recent vulnerabilities in Fluent Forms Pro Add On Pack

# Title CVE ID CVSS Researchers Date
1 Fluent Forms Pro 6.2.7 & Ninja Tables Pro 5.2.13 - Remote Code Execution via Backdoor 9.8 August 3, 2026
2 Fluent Forms Pro Add On Pack <= 6.2.6 - Authenticated (Subscriber+) PHP Object Injection to Arbitrary User Password Change via User Meta Field CVE-2026-15962 8.8 daroo July 25, 2026
3 Fluent Forms Pro Add On Pack <= 6.1.17 - Missing Authorization to Unauthenticated Arbitrary Attachment Deletion CVE-2026-2899 6.5 Prickly Cactus March 4, 2026
4 Fluent Forms Pro <= 6.1.17 - Unauthenticated Stored Cross-Site Scripting via Draft Form Submission CVE-2026-2365 7.2 Prickly Cactus March 4, 2026
5 Fluent Forms Pro Add On Pack <= 6.1.12 - Authenticated (Subscriber+) Server-Side Request Forgery via 'saveDataSource' CVE-2026-0632 5.4 andrea bocchetti February 8, 2026

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