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CVE-2026-7520 — The MailChimp Forms by MailMunch plugin for WordPress is vulnerable to unauthorized…

Key facts

CVE-2026-7520 is a High (8.1) vulnerability: The MailChimp Forms by MailMunch plugin for WordPress is vulnerable to unauthorized…. This entry ships a detection-only PoC and a Docker test lab.
CVE CVE-2026-7520
Severity High (8.1)
Detection / prevention —
PoC poc.py
Source 2026/CVE-2026-7520/

Details

English | 한국어

Description

The MailChimp Forms by MailMunch plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the sign_in() and sign_up() AJAX handlers in all versions up to, and including, 3.2.7. This makes it possible for authenticated attackers, with Subscriber-level access and above, to relink the site's MailMunch integration to an attacker-controlled MailMunch account by submitting attacker-supplied credentials. Once relinked, all subscriber data captured by the plugin's forms is delivered to the attacker, and the forms/landing pages rendered on the site are pulled from the attacker's MailMunch account.

Vulnerability Details

Property Value
CVE ID CVE-2026-7520
CVSS Score 8.1

Proof of Concept

Download

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-7520/poc.py

Usage

# Run PoC against target
python3 poc.py --target <TARGET_URL>

# With authentication
python3 poc.py --target <TARGET_URL> --username <USER> --password <PASS>

⚠️ Warning: This PoC is for authorized security testing only. It uses detection-only techniques and does not exploit or damage target systems.

Test Lab

This repository includes a Docker-based test environment with both vulnerable and patched applications.

Quick Start

# Clone and navigate to CVE directory
cd CVE-2026-7520

# Start both applications
docker-compose up -d

# Run tests
./run-tests.sh    # Linux/Mac
./run-tests.ps1   # Windows PowerShell

Application Endpoints

Application URL Status
Vulnerable App http://localhost:8080 Shows vulnerability
Patched App http://localhost:8081 Demonstrates fix

Directory Structure

├── README.md           # English documentation
├── README_KO.md        # Korean documentation
├── poc.py              # PoC detection script
├── docker-compose.yml  # Container orchestration
├── run-tests.sh        # Linux/Mac test runner
├── run-tests.ps1       # Windows test runner
├── vulnerable-app/     # Vulnerable version
│   ├── app.py
│   ├── Dockerfile
│   └── requirements.txt
└── patched-app/        # Fixed version
    ├── app.py
    ├── Dockerfile
    └── requirements.txt

References

  • https://plugins.trac.wordpress.org/browser/mailchimp-forms-by-mailmunch/tags/3.2.7/admin/class-mailchimp-mailmunch-admin.php#L126
  • https://plugins.trac.wordpress.org/browser/mailchimp-forms-by-mailmunch/tags/3.2.7/admin/class-mailchimp-mailmunch-admin.php#L134
  • https://plugins.trac.wordpress.org/browser/mailchimp-forms-by-mailmunch/tags/3.2.7/includes/class-mailchimp-mailmunch.php#L219
  • https://plugins.trac.wordpress.org/browser/mailchimp-forms-by-mailmunch/tags/3.2.7/includes/class-mailmunch-api.php#L354
  • https://plugins.trac.wordpress.org/browser/mailchimp-forms-by-mailmunch/tags/3.2.7/includes/class-mailmunch-api.php#L371
  • https://plugins.trac.wordpress.org/browser/mailchimp-forms-by-mailmunch/trunk/admin/class-mailchimp-mailmunch-admin.php#L134
  • https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&new=3593826%40mailchimp-forms-by-mailmunch%2Ftags%2F3.2.8&old=3445363%40mailchimp-forms-by-mailmunch%2Ftags%2F3.2.7
  • https://www.wordfence.com/threat-intel/vulnerabilities/id/c9d00ee8-b9df-4044-a5e2-320391d6c9b1?source=cve

Generated by PoC Generator on 2026-08-10T04:00:49.829881888

Frequently asked questions

What is CVE-2026-7520?

CVE-2026-7520 is a High (8.1) vulnerability: The MailChimp Forms by MailMunch plugin for WordPress is vulnerable to unauthorized…. This entry ships a detection-only PoC and a Docker test lab.

How do I detect CVE-2026-7520?

Run the detection-only PoC included with this entry against your Docker test lab to confirm whether a target is affected; pair it with your own IDS logging.

How do I block or mitigate CVE-2026-7520?

Upgrade to a fixed version per the vendor advisory; the NVD record lists the affected versions. Use the included PoC to verify your remediation.

For authorized security testing and research only. See the full source and NVD record.