---
id: "CVE-2026-109218"
kind: "vulnerability"
aliases: ["CVE-2026-109218"]
title: "WordPress Contact Manager plugin: unauthenticated arbitrary file upload via add_message"
severity: "critical"
cvss: 9.8
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["apache", "package", "php", "self-hosted", "wordpress"]
not_affected_if: ["managed-hosting", "nginx-or-non-mod-php", "plugin-not-installed"]
published_at: "2026-10-28T07:16:44+00:00"
first_seen_at: "2026-10-28T07:31:37+00:00"
updated_at: "2026-10-28T07:32:45+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-109218", "first_seen_at": "2026-10-28T07:31:37+00:00"}]
---

# WordPress Contact Manager plugin: unauthenticated arbitrary file upload via add_message

The Contact Manager WordPress plugin up to and including 9.1.2 lets unauthenticated visitors upload files through its add_message function because a trailing-dot trick bypasses the extension blacklist. On Apache with libapache2-mod-php, an uploaded .phar file may run as PHP, giving remote code execution if the attacker fetches it before it is deleted.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed plugin version in the WordPress admin plugins list or in `wp-content/plugins/` for the Contact Manager plugin; versions up to and including `9.1.2` are affected.
- Run `apache2 -v` and `dpkg -l | grep libapache2-mod-php` to see whether Apache with mod_php is in use.
- Check whether the plugin's upload directory is reachable over HTTP and whether PHP runs there.

## Fix

- Update the Contact Manager plugin to a version newer than `9.1.2`; the sources do not name the fixed version, so unknown.
- If no fixed version is available, disable or remove the plugin.
- Block PHP execution in upload directories and review web server logs for unexpected uploads.

## Timeline

- 2026-10-28T07:31:37+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-109218

## From the sources

The Contact Manager plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 9.1.2 via the add_message function. This is due to an incomplete extension blacklist that fails to detect dangerous extensions when a trailing dot causes the extension-derivation routine to return an empty string, which sanitize_file_name() then silently removes before the file is written to disk. This makes it possible for unauthenticated attackers to upload files that may be executable, which makes remote code execution possible. Successful code execution additionally requires the server to use Apache with libapache2-mod-php (which maps .phar to PHP by default) and the attacker to retrieve the uploaded file within the brief window before it is removed by unlink() at end of request.

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