Critical WordPress Plugin Flaw Allows Unauthenticated Remote Code Execution

A critical security vulnerability in the Mang Board WordPress plugin allows unauthenticated attackers to execute arbitrary code on affected servers. The National Vulnerability Database assigned the flaw CVE-2026-109219 with a CVSS score of 9.8, indicating a severe risk to any site using the plugin in versions up to and including 2.4.4.

The vulnerability stems from improper validation within the mbw_file_upload function. According to the NVD record, the plugin fails to validate file extensions on the attacker-supplied image_path parameter. While an allowlist is applied to the separate file_name parameter, the basename-derived filename from image_path bypasses this security control. This oversight permits the upload of executable files, leading to remote code execution.

Technical Context and Exploitation Conditions

The exploitation of this flaw relies on specific configuration settings that are enabled by default in the Mang Board plugin. The board must be configured to allow guest posts for the attack to succeed. This is the standard default mode for the plugin, meaning most installations are susceptible without additional configuration changes by the site administrator.

Furthermore, the required security nonce for the upload request is printed on every public board page. This makes the nonce readable by any unauthenticated visitor without requiring a WordPress login or credentials. The combination of default guest posting and publicly accessible nonces significantly lowers the barrier for exploitation, allowing attackers to craft valid requests from outside the network.

Affected Versions and Scope

All versions of the Mang Board plugin up to and including 2.4.4 are affected by this arbitrary file upload vulnerability. The weakness is classified under CWE-434, which relates to unrestricted upload of executable files. The NVD record confirms that the issue persists across the entire version history up to the specified cutoff, affecting any WordPress installation that has not updated beyond version 2.4.4.

Site administrators using the plugin should verify their current version immediately. Because the default configuration exposes the vulnerability, the risk is inherent in standard deployments. No fix has been confirmed yet in the source material.

What should you do?

Security professionals should audit their WordPress installations for the presence of the Mang Board plugin. If the plugin is installed in version 2.4.4 or earlier, the site is vulnerable to remote code execution. Administrators should check the plugin settings to see if guest posts are enabled, as this is the default state that facilitates exploitation.

What to do and how to stay safe: WordPress

• Verify the installed version of the Mang Board plugin and compare it against the affected range up to 2.4.4.
• Disable guest posting capabilities in the plugin settings if an immediate update is not possible, though this may impact functionality.
• Monitor server logs for unusual file upload activity or requests targeting the mbw_file_upload function.
• Once the vendor provides an update, apply it immediately to resolve the arbitrary file upload vulnerability.

Step-by-step guide: Risk-Based Vulnerability Management: Prioritize Fixes by Actual Danger

General security guidance from the Threat Times newsroom. It is not confirmed advice from the organisations named in this story.

Frequently asked questions

What is the CVSS score for CVE-2026-109219?

The National Vulnerability Database rates CVE-2026-109219 as CVSS 9.8 Critical.

Which versions of the Mang Board plugin are affected?

All versions up to and including 2.4.4 are vulnerable to this arbitrary file upload flaw.

Is authentication required to exploit this vulnerability?

No, the vulnerability can be exploited by unauthenticated attackers because the required nonce is publicly visible.