CVE-2026-15178 Overview
CVE-2026-15178 is an authorization bypass vulnerability in the Fluent Forms plugin for WordPress affecting all versions up to and including 6.2.5. The plugin fails to properly verify whether an authenticated user is authorized to perform sensitive actions. Attackers with Custom-level access or higher can read private form submissions, modify submission statuses, permanently delete submissions, and change global plugin settings. The flaw is tracked under CWE-862: Missing Authorization.
Critical Impact
Authenticated low-privilege WordPress users can access private form submission data and tamper with plugin configuration, compromising form data confidentiality and integrity.
Affected Products
- Fluent Forms plugin for WordPress, all versions up to and including 6.2.5
- WordPress sites running the plugin with Custom-level user roles enabled
- Sites patched by WordPress plugin changeset 3602478
Discovery Timeline
- 2026-10-10 - CVE-2026-15178 published to NVD
- 2026-10-13 - Last updated in NVD database
Technical Details for CVE-2026-15178
Vulnerability Analysis
Fluent Forms exposes several administrative actions through its Access Control List (ACL) module without verifying that the calling user holds the required capability. Any authenticated user with Custom-level access or above can invoke the affected endpoints and operate on data they should not be permitted to touch. The vendor patch, published in WordPress plugin changeset 3602478, modifies app/Modules/Acl/Acl.php to enforce proper capability checks before privileged operations execute.
The exposed functionality is broad. Attackers can enumerate and read private form submissions containing arbitrary user-supplied data, including personally identifiable information collected via contact or application forms. They can also mutate submission state by changing statuses or permanently deleting submissions, and they can modify global plugin settings that influence how all forms behave across the site.
Root Cause
The root cause is a missing authorization check in the plugin's ACL enforcement layer. The code grants access based on authentication rather than capability, so any logged-in user whose role satisfies a minimal threshold passes the gate.
Attack Vector
Exploitation requires network access to the WordPress site and valid credentials for a user with Custom-level privileges or higher. The attacker sends crafted requests to the affected plugin endpoints, which the ACL module processes without validating the required capability. No user interaction is required beyond the attacker's own authenticated session.
No verified public proof-of-concept is available at this time. Technical details are documented in the WordPress Plugin Changeset and the Wordfence Vulnerability Report.
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Stop Identity AttacksDetection Methods for CVE-2026-15178
Indicators of Compromise
- Unexpected changes to Fluent Forms global settings in the WordPress options table
- Form submissions deleted or status-modified by low-privilege user accounts
- Access log entries for Fluent Forms AJAX or REST endpoints originating from non-administrator sessions
- Unexplained reads of private submission data correlated with Custom-level user sessions
Detection Strategies
- Audit WordPress user roles and identify accounts with Custom-level capabilities that should not require Fluent Forms administrative access
- Review the Fluent Forms submission audit trail for status changes or deletions performed by non-administrative users
- Inspect web server access logs for admin-ajax.php or REST calls to Fluent Forms actions issued by sessions tied to low-privilege users
- Compare current plugin files against the version shipped in changeset 3602478 to confirm patch deployment
Monitoring Recommendations
- Enable WordPress activity logging to capture role usage, option changes, and plugin configuration edits
- Alert on bulk submission deletions or status transitions outside of normal administrator activity windows
- Monitor for new or modified Custom-level roles created after disclosure of this vulnerability
How to Mitigate CVE-2026-15178
Immediate Actions Required
- Update the Fluent Forms plugin to the version containing changeset 3602478 or later
- Review all WordPress user accounts with Custom-level or higher roles and remove unnecessary access
- Rotate credentials for any accounts suspected of being used to exercise the vulnerable endpoints
- Export and back up existing form submissions before investigating potential tampering
Patch Information
The vendor addressed the vulnerability by adding capability checks in app/Modules/Acl/Acl.php. The fix is published in WordPress plugin changeset 3602478. Site administrators should install the latest Fluent Forms release from the WordPress plugin repository.
Workarounds
- Restrict Custom-level and higher roles to trusted users only until the patch is applied
- Use a web application firewall rule to block Fluent Forms administrative actions from non-administrator sessions
- Temporarily deactivate the Fluent Forms plugin on sites where the patch cannot be applied immediately
# Verify the installed Fluent Forms version on a WordPress host
wp plugin get fluentform --field=version
# Update Fluent Forms to the latest patched release
wp plugin update fluentform
# List all users with elevated roles for review
wp user list --role=administrator,editor --fields=ID,user_login,user_email,roles
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
