---
id: "CVE-2026-118166"
page: "https://infrastack.ai/live/CVE-2026-118166"
kind: "vulnerability"
aliases: ["CVE-2026-118166"]
title: "WordPress Mailchimp plugin: unauthenticated visitors can run registered shortcodes"
severity: "medium"
cvss: 4.8
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["mailchimp-for-wordpress", "mc4wp", "package", "wordpress"]
not_affected_if: ["classic-shortcode-only", "no-request-derived-tags", "version-4.15.0-or-later"]
published_at: "2026-11-06T08:17:18+00:00"
first_seen_at: "2026-11-06T08:40:32+00:00"
updated_at: "2026-11-06T08:42:43+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-118166", "first_seen_at": "2026-11-06T08:40:32+00:00"}]
exploit_sources: []
---

# WordPress Mailchimp plugin: unauthenticated visitors can run registered shortcodes

Link for people: https://infrastack.ai/live/CVE-2026-118166 (this .md is for agents)

The MC4WP Mailchimp for WordPress plugin before 4.15.0 lets request-derived values in dynamic content tags be processed as shortcodes when a form is embedded with its block. An unauthenticated visitor can execute any registered shortcode with attacker-chosen attributes.

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

## How to check

- Check the installed version of the MC4WP: Mailchimp for WordPress plugin in the WordPress admin plugins list; it is affected below `4.15.0`.
- Look for a request-derived dynamic content tag (such as a URL or query parameter tag) in forms that are embedded with the MC4WP block.

## Fix

- MC4WP: Mailchimp for WordPress: upgrade to `4.15.0` or later.

## Timeline

- 2026-11-06T08:40:32+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-118166

## From the sources

The MC4WP: Mailchimp for WordPress WordPress plugin before 4.15.0 does not prevent request-derived values in its dynamic content tags from being processed as shortcodes when a form is embedded with its block, allowing unauthenticated visitors to execute arbitrary registered shortcodes with attacker-chosen attributes. This requires the site owner to have added a request-derived tag to the form content and to embed the form with the block rather than the classic shortcode.

---

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