CVE-2026-111832

Summary

The WP Mailster plugin allows unauthenticated users to upload files of any type, including dangerous web-shells, due to missing file-type restrictions.

Exploitability

Exploitation is straightforward for an attacker with network access and requires no authentication or user interaction.

Blast radius

Successful exploitation could lead to full server compromise via remote code execution, enabling data theft, site defacement, or lateral movement.

Detection

Look for HTTP POST requests to the plugin's upload endpoint (e.g., /wp-admin/admin-ajax.php?action=mailster_upload) containing a file with a web-shell extension (e.g., .php, .phtml) and an unusually large or suspicious filename pattern in access logs.

Prioritized remediation

Upgrade to WP Mailster version 1.9.1.1 or later, which patches the unrestricted upload vulnerability.

Analysis generated locally by garnet-coder (no data left the box). AI-assisted — verify against primary sources before acting.