What’s Vulnerable › Vulnerabilities

CVE-2026-4160: Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder <= 6.1.21 - Insecure Direct Object Reference in Stripe SCA Confirmation to Unauthenticated Payment Status Modification

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-16 · updated 2026-06-17
• Weakness: CWE-639

Description

The Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder plugin for WordPress is vulnerable to Insecure Direct Object Reference via the 'submission_id' parameter in versions up to, and including, 6.1.21. This is due to missing authorization and ownership validation on a user controlled key in the Stripe SCA confirmation AJAX endpoint. This makes it possible for unauthenticated attackers to modify payment status of targeted pending submissions (for example, setting the status to "failed").

Affected products

• techjewel Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder: 6.1.21

References

• https://plugins.trac.wordpress.org/changeset/3496638/fluentform
• https://www.wordfence.com/threat-intel/vulnerabilities/id/154fc656-3a33-4783-a941-10bb848244b3?source=cve

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