Fluent Forms <= 6.2.8 - Unauthenticated Sensitive Information Exposure via Insecure Direct Object Reference and Weak Transaction Hash in 'transaction' Parameter

5.3
Authorization Bypass Through User-Controlled Key
CVE CVE-2026-17567
CVSS 5.3 (Medium)
Publicly Published July 30, 2026
Last Updated July 31, 2026
Researcher ChinhNguyen

Description

The Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 6.2.8 via the 'transaction' parameter due to missing validation on a user controlled key. This makes it possible for unauthenticated attackers to brute-force valid transaction hashes and view sensitive payment receipt data including customer name, email address, billing address, order items, payment method, and payment status belonging to other users. Because submission ID, form ID, and transaction creation time are either observable or guessable by an attacker, the effective brute-force space is bounded to approximately 900 candidates per second per (submission, form) pair, making exploitation practical without any prior authentication or account.

References

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Vulnerability Details for Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder

Software Type Plugin
Software Slug fluentform (view on wordpress.org)
Patched? Yes
Remediation Update to version 6.2.9, or a newer patched version
Affected Version
  • <= 6.2.8
Patched Version
  • 6.2.9

Recent vulnerabilities in Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder

# Title CVE ID CVSS Researchers Date
1 Fluent Forms <= 6.2.11 - Unauthenticated Stored Cross-Site Scripting via Notification Smartcode Values CVE-2026-18146 7.2 Adrien Brunner August 12, 2026
2 Fluent Forms <= 6.2.4 - Insecure Direct Object Reference to Authenticated (Form Manager+) Cross-Form Submission Entry Deletion CVE-2026-11578 4.3 Muni Nitish Kumar Yaddala August 11, 2026
3 Fluent Forms <= 6.2.0 - Insecure Direct Object Reference to Authenticated (Subscriber+) Subscription Cancellation CVE-2026-11880 4.3 Pedro Pinho August 10, 2026
4 Fluent Forms <= 6.2.8 - Reflected Cross-Site Scripting via 'param' CVE-2026-17571 6.1 Osvaldo Noe Gonzalez Del Rio (Os) July 31, 2026
5 Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder < 6.2.6 - Authenticated (Contributor+) Stored Cross-Site Scripting CVE-2026-11881 6.4 Muni Nitish Kumar Yaddala July 30, 2026
6 Fluent Forms <= 6.2.7 - Unauthenticated Stored Cross-Site Scripting via Name Field Nested `password` Member CVE-2026-16655 7.2 daroo July 28, 2026
7 Fluent Forms <= 6.2.1 - Incorrect Authorization to Authenticated (Subscriber+) Arbitrary Subscription Cancellation via 'subscription_id' CVE-2026-5069 5.4 Fernando Mecozzi July 9, 2026
8 Fluent Forms <= 6.2.0 - Authenticated (Subscriber+) Authorization Bypass via 'table' Parameter CVE-2026-5395 8.2 Sander Horsman May 13, 2026
9 Fluent Forms <= 6.1.21 - Authenticated (Subscriber+) Authorization Bypass via 'form_id' Parameter CVE-2026-5396 8.2 Sander Horsman May 13, 2026
10 Fluent Forms <= 6.2.1 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'permission_message' Shortcode Attribute CVE-2026-6828 6.4 zaim May 12, 2026

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