CVE-2026-111834: Mang Board WP Plugin — Critical Unrestricted File Upload Leads to Web Shell

Executive Summary

A critical unrestricted file upload vulnerability has been published for Mang Board WP (mangboard), a WordPress bulletin-board plugin by Kitae Park. Tracked as CVE-2026-111834 with a CVSS score of 9.9, the flaw allows an attacker to upload a web shell to the web server.

The NVD entry was published on 2026-10-21 and lists affected versions as from n/a through 2.4.4.

Vulnerability Overview

Root Cause

The plugin fails to restrict dangerous file types on upload. A crafted upload can place an executable script on the server, giving the attacker a persistent web-based command shell.

Impact

• Remote code execution as the web server user
• Complete site compromise, including theft of database credentials and user data
• Persistence via backdoors and rogue administrator accounts
• Pivoting to other applications on the same host

Because the plugin powers community boards that accept user submissions, upload functionality is likely internet-facing.

Remediation

1. Update Mang Board WP past version 2.4.4 once a fixed release is available; check the plugin repository for status.
2. If no fix exists, deactivate and remove the plugin.
3. Inspect upload directories for unexpected .php, .phtml, or other executable files.
4. Review logs for upload requests followed by direct requests to the new file.
5. Rotate WordPress and database credentials if compromise is suspected.

Hardening

• Deny script execution in upload directories
• Enforce server-side allow-lists for file extensions and MIME types
• Use a WAF and file-integrity monitoring

Key Takeaways

1. CVSS 9.9 — near-maximum severity
2. Versions through 2.4.4 are affected
3. The flaw gives code execution via web shell
4. Remove or patch the plugin promptly; unpatched upload flaws are quickly scanned for at scale

References

• NVD — CVE-2026-111834
• OWASP — Unrestricted File Upload