Contest Gallery <= 28.1.5 - Unauthenticated Privilege Escalation Admin Account Takeover via Registration Confirmation Email-to-ID Type Confusion
| CVE | CVE-2026-4021 |
|---|---|
| CVSS | 8.1 (High) |
| Publicly Published | March 23, 2026 |
| Last Updated | April 1, 2026 |
| Researcher |
Supakiad S. (m3ez)
- E-CQURITY (Thailand)
|
Description
The Contest Gallery plugin for WordPress is vulnerable to an authentication bypass leading to admin account takeover in all versions up to, and including, 28.1.5. This is due to the email confirmation handler in `users-registry-check-after-email-or-pin-confirmation.php` using the user's email string in a `WHERE ID = %s` clause instead of the numeric user ID, combined with an unauthenticated key-based login endpoint in `ajax-functions-frontend.php`. When the non-default `RegMailOptional=1` setting is enabled, an attacker can register with a crafted email starting with the target user ID (e.g., `1poc@example.test`), trigger the confirmation flow to overwrite the admin's `user_activation_key` via MySQL integer coercion, and then use the `post_cg1l_login_user_by_key` AJAX action to authenticate as the admin without any credentials. This makes it possible for unauthenticated attackers to take over any WordPress administrator account and gain full site control.
Learn more about Authentication Bypass vulnerabilities and how to prevent them.
References
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
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Vulnerability Details for Contest Gallery – Upload & Vote Photos, Media, Sell with PayPal & Stripe
| Software Type | Plugin |
|---|---|
| Software Slug | contest-gallery (view on wordpress.org) |
| Patched? | Yes |
| Remediation | Update to version 28.1.6, or a newer patched version |
| Affected Version |
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| Patched Version |
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Recent vulnerabilities in Contest Gallery – Upload & Vote Photos, Media, Sell with PayPal & Stripe
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