CVE-2026-4021
8.1 · HIGHOverview
CVE-2026-4021 is a high-severity vulnerability. It was published on March 24, 2026 and has a CVSS 3.1 base score of 8.1 (HIGH).
This vulnerability has a CVSS 3.1 base score of 8.1, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical 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., `[email protected]`), 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.
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
References
Frequently Asked Questions
What is CVE-2026-4021?
CVE-2026-4021 is a high-severity vulnerability. It was published on March 24, 2026 and has a CVSS 3.1 base score of 8.1 (HIGH).
How severe is CVE-2026-4021?
This vulnerability has a CVSS 3.1 base score of 8.1, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-4021?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-4021?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-4021 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
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