techjewel Fluent Forms Plugin 6.1.21 on WordPress AJAX Endpoint submission_id authorization

Summaryinfo

A vulnerability marked as critical has been reported in techjewel Fluent Forms Plugin 6.1.21 on WordPress. This vulnerability affects unknown code of the component AJAX Endpoint. Performing a manipulation of the argument submission_id results in authorization. This vulnerability is identified as CVE-2026-4160. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability classified as critical has been found in techjewel Fluent Forms Plugin 6.1.21 on WordPress. This affects an unknown code of the component AJAX Endpoint. The manipulation of the argument submission_id with an unknown input leads to a authorization vulnerability. CWE is classifying the issue as CWE-639. The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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").

The weakness was released by Prickly Cactus. The advisory is shared at wordfence.com. This vulnerability is uniquely identified as CVE-2026-4160 since 03/13/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 04/16/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• WordPress Plugin

Vendor

• techjewel

Name

• Fluent Forms Plugin

Version

• 6.1.21

CPE 2.3info

• 🔒

CPE 2.2info

• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion