Security Alert Summary
The User Frontend WordPress plugin contains a PHP object injection vulnerability that can be triggered when a submitted post is reopened in the plugin’s frontend editing form. Authenticated users with subscriber-level access and above can supply serialized data that is not prevented from being deserialized, which may lead to remote code execution if a suitable gadget chain exists on the site.
CVE Details
- CVE ID:
CVE-2026-19116 - Affected component: User Frontend WordPress plugin
- Affected versions: versions less than 4.3.11
- Published: September 2, 2026 at 06:17:16 AM UTC
- Last modified: September 2, 2026 at 11:17:19 AM UTC
- CVSS v3.1: Base score 8.8, severity HIGH, vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Authentication / Privileges / User interaction: Requires an authenticated user with low privileges (subscriber-level access or higher). No user interaction required once the user is authenticated.
- Impact (CIA): Confidentiality: High; Integrity: High; Availability: High
- CWE / Weakness ID: CWE-502 (Deserialization of Untrusted Data)
Technical Details
The plugin does not prevent user-supplied field values from being deserialized when a submitted post is reopened in its frontend editing form. This allows an authenticated user with subscriber-level access or higher to submit crafted serialized objects that are deserialized by the application, enabling PHP Object Injection.
Because the vulnerability involves unsafe deserialization of user-controlled data, an attacker who can provide a suitable gadget chain within the application’s available classes and object structure may achieve remote code execution. The CVE description does not name specific functions or endpoints; it identifies the frontend editing form reopening process as the point where deserialization of user-supplied field values occurs and where proper validation or sanitization is missing.
The practical impact depends on whether exploitable gadget chains are present in the site code, plugins, or themes. If present, the vulnerability can allow an attacker to execute arbitrary PHP code under the web server process.
How This Could Impact Your Website
Consider a small team managing a WordPress site: the site owner, an editor on staff, and an external contractor who contributes content. If a contractor or staff member with subscriber-level access reopens a post in the frontend editing form and the plugin accepts and deserializes crafted field values, an attacker could exploit that action to execute code or gain elevated access.
Realistic consequences include exposure of internal user data (for example, user email addresses), altered or injected content, and increased risk of targeted phishing or social engineering campaigns using obtained information. The exploitation path requires authenticated access at subscriber level or higher and the presence of a suitable gadget chain, so the risk is not equivalent to immediate full-site takeover in all environments.
If youre unsure whether your site is affected or how to assess your current user roles and plugins, it may be worth having a professional review.
Recommended Actions
- Update the affected plugin as soon as a patched version is available.
- Review and reduce unnecessary user roles, especially contributor and subscriber privileges.
- Enforce strong passwords and enable two-factor authentication for editors and administrators.
- Remove unused or unmaintained plugins and themes.
- Monitor site activity and logs for unusual behavior, such as unexpected user activity or serialized payloads submitted via frontend forms.
If youd like help reviewing your plugins, user roles, or overall WordPress security posture, our team at Freshy is happy to help.
