Subscriber Privilege Escalation in Fluent Forms Pro Add On Pack <= 6.2.12 versions.

The Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Notification Smartcode Values in all versions up to, and including, 6.2.11 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts that execute in the browser of an administrator (or any user with the Fluent Forms entry-viewing capability) when they view the form's entry Submission Logs in the WordPress admin dashboard. Exploitation requires that a site administrator or Fluent Forms manager has configured an email notification whose subject or static (direct) Send To value references an attacker-influenced Smartcode such as an inputpassword field value, a cookie value, or submission.response.

Fluent Forms Pro 6.2.7 contains an embedded malicious code vulnerability introduced via a tampered plugin build served through a decommissioned update server. The tampered build introduced a rogue PHP file (libs/class-license-sync.php), loaded via a requireonce directive added to fluentformpro.php, that established a backdoor REST API endpoint, dropped persistent PHP files in mu-plugins and uploads directories, installed a passwordless administrator account, and registered scheduled tasks that survived plugin removal.

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.

The Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via 'param' in all versions up to, and including, 6.2.8 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link.

The Fluent Forms WordPress plugin before 6.2.6 does not sanitise and escape one of its form field configuration settings before outputting it inside an inline script when a form is rendered, which could allow users with a role as low as Contributor (with delegated form-management permission, and therefore lacking the unfilteredhtml capability, e.g. in a multisite setup) to perform Stored Cross-Site Scripting attacks that execute in the browser of any visitor who loads the form, including administrators previewing it.

The Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Name Field Nested password Member in all versions up to, and including, 6.2.7 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

The Fluent Forms Pro Add On Pack plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 6.2.6 via deserialization of untrusted input. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject a PHP Object. The additional presence of a POP chain allows attackers to change user passwords and potentially take over administrator accounts. Note: This can only be exploited if user update integration is enabled and a user meta field is mapped.

The Fluent Forms WordPress plugin before 6.2.5 does not properly restrict the deletion of form submission entries to the forms a restricted Manager is authorized to manage, allowing a Manager limited to specific forms to permanently delete submission entries belonging to other forms. This requires a non-default configuration in which an administrator has created at least one Manager restricted to specific forms.

The Fluent Forms WordPress plugin before 6.2.1 does not properly verify ownership before processing a subscription cancellation request, allowing authenticated users with a low-privilege account to cancel subscriptions belonging to other users.

The Contact Form Plugin by Fluent Forms for Quiz, Survey, and Drag & Drop WP Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the ‘subject’ parameter in versions up to, and including, 5.1.16 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level permissions and above, and access granted by an administrator, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

The Contact Form Plugin by Fluent Forms for Quiz, Survey, and Drag & Drop WP Form Builder plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 5.1.15 via deserialization of untrusted input in the extractDynamicValues function. This makes it possible for authenticated attackers, with contributor-level access and above, to inject a PHP Object. If a POP chain is present via an additional plugin or theme installed on the target system, it could allow the attacker to delete arbitrary files, retrieve sensitive data, or execute code. Successful exploitation requires the attacker to have "View Form" and "Manage Form" permissions, which must be explicitly set by an administrator. However, this requirement can be bypassed when this vulnerability is chained with CVE-2024-2771.

The Fluent Forms plugin for WordPress by Fluent Forms plugin for WordPress is vulnerable to Stored Cross-Site Scripting in all versions up to, and including, 5.1.9 due to insufficient input sanitization and output escaping. This makes it possible for attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The exploitation level depends on who is granted the right to create forms by an administrator. This level can be as low as contributor, but by default is admin.

The Fluent Forms plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the form-submission.js script in all versions up to, and including, 6.0.2 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

The Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder plugin for WordPress is vulnerable to IP Address Spoofing in all versions up to, and including, 5.2.12 due to insufficient IP address validation and use of user-supplied HTTP headers as a primary method for IP retrieval. This makes it possible for unauthenticated attackers spoof their IP address and submit forms that may have IP-based restrictions.

The Contact Form Plugin by Fluent Forms for Quiz, Survey, and Drag & Drop WP Form Builder plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the /wp-json/fluentform/v1/global-settings REST API endpoint in all versions up to, and including, 5.1.16. This makes it possible for unauthenticated attackers to modify all of the plugin's settings.

The Contact Form Plugin by Fluent Forms for Quiz, Survey, and Drag & Drop WP Form Builder plugin for WordPress is vulnerable to privilege escalation due to a missing capability check on the /wp-json/fluentform/v1/managers REST API endpoint in all versions up to, and including, 5.1.16. This makes it possible for unauthenticated attackers to grant users with Fluent Form management permissions which gives them access to all of the plugin's settings and features. This also makes it possible for unauthenticated attackers to delete manager accounts.

The Contact Form Plugin by Fluent Forms for Quiz, Survey, and Drag & Drop WP Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via form settings in all versions up to, and including, 5.1.13 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with access to the Fluent Forms settings, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This can be chained with CVE-2024-2771 for a low-privileged user to inject malicious web scripts.

The Contact Form Plugin by Fluent Forms for Quiz, Survey, and Drag & Drop WP Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the ‘description’ and 'btntxt' parameters in all versions up to, and including, 5.1.19 due to insufficient input sanitization and output escaping. This makes it possible for attackers with the Form Manager permissions and Subscriber+ user role, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

The Contact Form Plugin by Fluent Forms for Quiz, Survey, and Drag & Drop WP Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via form label fields in all versions up to, and including, 5.1.19 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with access to edit forms (administrator by default), to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

The Contact Form Plugin by Fluent Forms for Quiz, Survey, and Drag & Drop WP Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the form's subject parameter in all versions up to, and including, 5.2.6 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

The Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder plugin for WordPress is vulnerable to PHP Object Injection in versions 5.1.16 to 6.1.1 via deserialization of untrusted input in the parseUserProperties function. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject a PHP Object. The additional presence of a POP chain allows attackers to read arbitrary files. If allowurlinclude is enabled on the server, remote code execution is possible. While the vendor patched this issue in version 6.1.0, the patch caused a fatal error in the vulnerable code, due to a missing class import, so we consider 6.1.2 to be the most complete and best patched version

The Fluent Forms WordPress plugin before 5.2.1 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfilteredhtml capability is disallowed (for example in multisite setup).