Security Alert Summary
The Simple Membership MailChimp Integration WordPress plugin before 1.9.8 lacks Cross-Site Request Forgery (CSRF) protections on its settings page. An attacker can trick a logged-in administrator into changing the configured third-party API key, causing future member registration data (name, email, membership level) to be sent to an attacker-controlled account.
CVE Details
- CVE ID:
CVE-2026-8151 - Affected component: Simple Membership MailChimp Integration (WordPress plugin)
- Affected versions: All versions before 1.9.8
- Published: September 2, 2026 at 3:17:46 PM UTC
- Last modified: September 2, 2026 at 3:17:46 PM UTC
- CVSS v3.1: Base Score 5.4 – MEDIUM
- Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
- Authentication / Privileges / User interaction: Privileges Required: NONE; User Interaction: REQUIRED; Attack Vector: NETWORK; Attack Complexity: LOW
- Primary impact: Confidentiality: LOW; Integrity: LOW; Availability: NONE
- CWE / weakness: CWE-352 (Cross-Site Request Forgery)
Technical Details
The plugin’s settings page does not implement CSRF protections, allowing a remote attacker to craft a request that an authenticated administrator could be induced to submit. By replacing the configured MailChimp API key, the attacker redirects subsequent member registration data to an account they control. The description identifies missing CSRF checks on the settings page as the root cause.
A code reference included in the advisory points to the plugin admin menu file swpm-mailchimp-admin-menu.php, which is associated with the settings interface. No additional functions or REST endpoints are named in the provided data.
Impact is limited to the data sent to the MailChimp integration: newly registered members’ name, email, and membership level are forwarded to the attacker-controlled third-party account. The vulnerability does not, based on the provided information, indicate direct remote code execution or full site takeover.
How This Could Impact Your Website
Consider a small membership site with an owner, an internal staff editor who manages members, and an external contractor who occasionally assists with site content. If the contractor or staff member is an authenticated administrator and is targeted with a crafted link or webpage, an attacker could cause the site’s MailChimp API key to be replaced without obvious signs. After the change, new member signups would be sent to the attacker-controlled MailChimp account.
Practical consequences include exposure of newly registered users’ names and email addresses and an increased risk of targeted phishing or social engineering campaigns against members. This may also reduce trust in communications sent from the site until the integration is restored to a legitimate account.
If you\’re unsure whether your site is affected or how to assess your current user roles and plugins, it may be worth having a professional review of your setup.
Recommended Actions
- Update the affected plugin as soon as a patched version is available.
- Review and reduce unnecessary user roles, especially administrator and contributor accounts.
- Enforce strong passwords and enable two-factor authentication for editors and administrators.
- Remove unused or unmaintained plugins from the site.
- Monitor site activity and logs for unusual behavior, including unexpected changes to plugin settings or API keys.
If you\’d like help reviewing your plugins, user roles, or overall WordPress security posture, our team at Freshy is happy to help.
