PHP
CVE-2026-2428
HIGH
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Lifecycle Timeline
2DescriptionCVE.org
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).
AnalysisAI
Fluent Forms Pro Add On Pack for WordPress versions up to 6.1.17 fail to verify PayPal Instant Payment Notifications by default, allowing unauthenticated attackers to forge payment confirmations and mark unpaid submissions as paid. An attacker can exploit this to trigger post-payment automation including email delivery, access grants, and digital product distribution without actual payment. The vulnerability affects all installations that have not manually enabled IPN verification and currently lacks a patch.
Technical ContextAI
This vulnerability (CWE-345: Insufficient Verification of Data Authenticity) affects Fluent Forms Pro Add On Pack (WordPress plugin). 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 submissi
Affected ProductsAI
Vendor: WordPress. Product: Fluent Forms Pro Add On Pack (WordPress plugin). Versions: up to 6.1.17..
RemediationAI
Monitor vendor advisories for a patch. Restrict network access to the affected service where possible.
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