Why Unauthenticated Admin Takeovers Keep Happening in WordPress Plugins CVE-2025-15027
Overview
CVE-2025-15027 is a critical privilege escalation vulnerability affecting the JAY Login & Register plugin for WordPress. All versions up to and including 2.6.03 are vulnerable.
The flaw allows an unauthenticated attacker to escalate their privileges to administrator, resulting in a full WordPress site takeover. No user account, login, or prior access is required.
This vulnerability is a clear example of a broader and recurring issue in the WordPress ecosystem: improper privilege management in plugins that handle user authentication and registration.
What Is the JAY Login & Register Plugin Used For?
The JAY Login & Register plugin is designed to customize and extend WordPress authentication workflows. It is commonly used to:
- Provide custom login and registration forms
- Handle AJAX-based user creation
- Improve onboarding and user experience
- Replace or extend WordPress’s default registration flow
Plugins like this are popular because many WordPress sites operate as:
- Membership platforms
- Communities
- Client portals
- E-commerce or gated-content sites
However, plugins that manage user creation and user metadata operate in one of the most sensitive security areas of WordPress.
What Is the Vulnerability?
The vulnerability exists in the function:
jay_login_register_ajax_create_final_user
This function allows arbitrary user meta updates without properly validating permissions.
In WordPress, user roles and capabilities are stored as user metadata. If an attacker can update certain meta keys, they can directly control a user’s role.
Because this function is accessible through an unauthenticated AJAX endpoint and does not enforce proper authorization checks, an attacker can:
- Send a crafted request to the endpoint
- Modify user metadata
- Assign themselves the administrator role
All of this can be done without logging in.
Why No Account Is Required
WordPress AJAX actions can be registered for:
- Authenticated users (wp_ajax_*)
- Unauthenticated users (wp_ajax_nopriv_*)
This vulnerable function is reachable through the unauthenticated path, which is why no account or credentials are required to exploit CVE-2025-15027.
This turns the vulnerability from a simple privilege escalation into a complete unauthenticated admin takeover.
Impact of Exploitation
Once an attacker gains administrator access, they can:
- Install malicious plugins or themes
- Upload web shells
- Inject malware or spam
- Steal user data and credentials
- Create persistent backdoor accounts
At that point, the WordPress site must be considered fully compromised.
CVSS Severity and Metrics
The vulnerability has been assessed by the CNA Wordfence with the following score:
Base Score: 9.8 (Critical)
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Although the NIST CVSS score differs, this discrepancy is common for WordPress plugin vulnerabilities. CNA scores provided by Wordfence often better reflect real-world exploitability, especially for unauthenticated plugin flaws.
Weakness Classification
CWE-269: Improper Privilege Management
This CWE category accurately reflects the root cause of the issue: insufficient controls around who is allowed to modify security-sensitive user attributes.
Why Vulnerabilities Like This Keep Appearing in WordPress Plugins
CVE-2025-15027 is not an isolated case. Similar issues appear repeatedly across the WordPress ecosystem due to several systemic factors:
- User Meta Is Extremely Powerful: Developers often underestimate how much control user meta provides over roles and capabilities.
- AJAX Endpoints Are Easy to Expose: WordPress makes it simple to create AJAX handlers, but also makes it easy to forget authentication and authorization checks.
- Plugins Reimplement Core Authentication Logic: Many plugins attempt to improve or customize login and registration without fully understanding WordPress’s security model.
- Scale Amplifies Risk: Even moderately popular plugins can be installed on thousands of sites, turning a single flaw into a widespread issue.
Affected Versions
JAY Login & Register plugin: all versions ≤ 2.6.03
Any site running an affected version should be considered vulnerable.
Recommended Mitigation Steps
WordPress site owners should take the following actions immediately:
- Update the plugin if a fixed version is available
- Disable or remove the plugin if it is no longer required
- Audit administrator accounts for unauthorized users
- Reset passwords for all privileged accounts
- Scan the site for malicious plugins, themes, or files
If the plugin is unmaintained, replacing it with a better-audited alternative is strongly recommended.
Conclusion
CVE-2025-15027 demonstrates how a single missing authorization check can lead to a complete WordPress site takeover.