Frontend Admin by DynamiApps CVE-2026-6226: Brief Summary of Unauthenticated Privilege Escalation via Form Configuration Injection

Introduction

A newly disclosed vulnerability in the Frontend Admin by DynamiApps WordPress plugin allows unauthenticated attackers to create administrator accounts by injecting a crafted form configuration into the plugin's submission pipeline, effectively turning the plugin's own form processing logic against itself. With a CVSS score of 8.8 and a trivially low exploitation barrier, this flaw represents a serious risk for any WordPress site running the affected plugin.

Frontend Admin by DynamiApps (plugin slug: acf-frontend-form-element) is a WordPress plugin that enables site owners to display admin forms on the frontend, allowing clients and users to edit content without accessing the WordPress dashboard. The plugin is hosted on the official WordPress.org repository and, based on Wordfence's bug bounty tier structure, likely has 30,000 or more active installations. It occupies a niche in the WordPress ecosystem for sites that need frontend content management workflows, particularly those built with Advanced Custom Fields (ACF) and Elementor.

Technical Information

CVE-2026-6226 is classified under CWE-269 (Improper Privilege Management) and carries a CVSS v3.1 vector of CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, yielding a score of 8.8. It is worth noting a discrepancy: the vulnerability description explicitly states the flaw is "unauthenticated," which would correspond to PR:N and a score of 9.8. The PR:L designation may reflect an assessment that some minimal WordPress context (such as a nonce or session state) is needed, or it may simply be a scoring inconsistency. Organizations should treat this as at least an 8.8 and potentially a 9.8 risk depending on their deployment.

Root Cause

The fundamental design error is that the plugin trusts user input to define the form schema. Rather than loading form definitions exclusively from the server side database, the plugin accepts and processes form configuration data directly from $_POST['_acf_form'] when it is submitted as an array. This violates the principle that configuration data must originate from a trusted source, not from user controllable request parameters.

Attack Chain

The exploitation proceeds through four stages, each involving a distinct source file in the plugin:

Stage 1: Form Definition Injection (submit.php, line 124)

The form submission handler reads $_POST['_acf_form'] to identify which form to process. Under normal operation, this value is a scalar form ID (an integer), and the validate_form() function performs a database lookup to retrieve the legitimate form configuration. However, when an attacker submits $_POST['_acf_form'] as an array instead of a form ID, the validate_form() function in display.php (line 245) bypasses the database lookup entirely and directly processes the attacker supplied array as the form definition.

Stage 2: Record Data Preservation (display.php, line 245)

After the spoofed form passes validation, the create_record() function preserves any attacker supplied record data present in the submission. Instead of constructing the record solely from server side trusted configuration, the function accepts and carries forward the attacker's data.

Stage 3: Field Definition Fallback (user.php, line 458)

When the user action's run() function attempts to locate field definitions for processing, it falls back to the attacker controlled $form['fields'] array from the injected form structure when legitimate fields cannot be found in the database. At this point, the attacker effectively controls the entire field schema the plugin uses to process the submission.

Stage 4: Role Options Spoofing (class-role.php, line 107)

The role field's pre_update_value() validation function reads $field['role_options'] from the field definition to determine which roles are permitted for assignment. Because the attacker controls the entire field definition through the injected form, they can set $field['role_options'] to ['administrator'], causing the security check to treat the administrator role as an allowed option. The attacker submits a role value of administrator, which passes the spoofed validation, and a new administrator account is created.

Key Source Code Files

Each stage compounds the trust violation. The plugin never verifies that the form definition originated from the database, never validates that field definitions are legitimate, and never independently checks whether the requested role is actually permitted by the site's configuration. The result is a complete authorization bypass from a single crafted POST request.

Affected Systems and Versions

All versions of the Frontend Admin by DynamiApps plugin (slug: acf-frontend-form-element) up to and including version 3.29.2 are vulnerable. Version 3.29.3 contains the fix, as documented in Changeset 3525193.

Any WordPress site running the affected plugin versions with frontend form functionality enabled is at risk. The vulnerability does not require any specific configuration beyond the plugin being active; the default form submission endpoint is sufficient for exploitation.

Vendor Security History

The Frontend Admin plugin has a well documented pattern of authorization failures. The Wordfence vulnerability database lists at least six distinct vulnerability entries for this plugin:

OpenCVE also lists a vulnerability involving improper missing encryption exception handling on the fea_encrypt function.

This history reveals that each patch addresses a specific symptom rather than the underlying design flaw of trusting client supplied data for configuration and authorization decisions. Multiple critical and high severity privilege escalation vulnerabilities in 2026 alone suggest that the plugin's architecture has not undergone a comprehensive security review. Organizations relying on this plugin should factor this track record into their risk assessment and consider whether alternative solutions with stronger security postures are available.

References

• Wordfence Advisory: Frontend Admin by DynamiApps <= 3.29.2 Unauthenticated Privilege Escalation via Form Configuration Injection
• CVE Record: CVE-2026-6226
• NVD: CVE-2026-6228 (Related Vulnerability)
• Changeset 3525193: Patch for acf-frontend-form-element
• Source: class-role.php (tag 3.28.33)
• Source: user.php (tag 3.28.33)
• Source: display.php (tag 3.28.33)
• Source: submit.php (tag 3.28.33)
• Source: class-role.php (trunk)
• Source: user.php (trunk)
• Source: display.php (trunk)
• Source: submit.php (trunk)
• Wordfence Vulnerability Database: Frontend Admin by DynamiApps
• WordPress.org Plugin Page: Frontend Admin by DynamiApps
• DynamiApps: Frontend Admin Product Page
• Patchstack: Frontend Admin Vulnerability Disclosure Program
• OpenCVE: Frontend Admin CVEs and Security Vulnerabilities
• wp-firewall.com: DynamiApps Frontend Admin Privilege Escalation Alert (CVE-2026-6228)
• VulnCheck: State of Exploitation 2026