CVE-2026-92435 in Mailchimp for WooCommerce Plugin
Summary
by MITRE • 09/19/2026
The Mailchimp for WooCommerce WordPress plugin before 6.1.1 does not verify that the requesting user holds the required capability in the permission callback for several of its REST API routes, allowing unauthenticated users to reach administrator-oriented endpoints and trigger a persistent state change.
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Analysis
by VulDB Data Team • 09/19/2026
The vulnerability identified in Mailchimp for WooCommerce versions prior to 6.1.1 represents a critical failure in access control mechanisms within the plugin's implementation of the WordPress REST API. This flaw stems from an insufficient verification of user capabilities during the permission callback phase, which is designed to act as a gatekeeper before any endpoint logic is executed. In standard web application architecture, particularly within content management systems like WordPress, every request intended for administrative or sensitive operations must be authenticated and authorized based on predefined roles and permissions. The absence of this check in several REST API routes means that the system fails to distinguish between legitimate administrators and unauthenticated external actors, effectively bypassing the security boundary meant to protect these functions.
From a technical perspective, the core issue lies in the permission callback function associated with specific REST endpoints not returning false or denying access when the requesting user lacks the necessary administrative privileges. Instead of validating that the current user possesses capabilities such as manage_woocommerce or other high-level permissions required for state-altering operations, the code proceeds to execute the endpoint's main logic regardless of the requester's identity. This allows unauthenticated users to send HTTP requests directly to these endpoints without providing valid credentials or session tokens. The lack of input validation regarding the user context transforms what should be protected administrative actions into publicly accessible functions that can be triggered by any entity on the internet, including automated bots and malicious scripts.
The operational impact of this vulnerability is severe due to its potential for persistent state changes. Because the affected endpoints allow unauthenticated users to modify plugin settings or trigger backend processes, attackers can manipulate the configuration of a WooCommerce store without authorization. This could lead to unauthorized modifications in email marketing configurations, customer data handling preferences, or integration settings with Mailchimp services. Such alterations can disrupt business operations, compromise sensitive customer information by altering how it is processed or transmitted, and potentially serve as an initial vector for further attacks against the underlying WordPress installation if those state changes expose additional attack surfaces or weaken other security controls.
This vulnerability aligns closely with CWE-284, which describes Improper Access Control, specifically reflecting a failure to enforce proper authorization checks before allowing access to sensitive resources. Furthermore, in the context of the MITRE ATT&CK framework for enterprise security, this flaw facilitates techniques associated with Initial Access and Privilege Escalation by allowing unauthenticated actors to perform actions typically reserved for privileged users. The ability to trigger persistent state changes also touches upon aspects of Impact, where an attacker can alter system behavior or data integrity in ways that persist beyond the immediate exploitation event.
To mitigate this risk, administrators must upgrade the Mailchimp for WooCommerce plugin to version 6.1.1 or later immediately, as these updates include patches that enforce proper capability verification within the REST API permission callbacks. Until the update is applied, it is advisable to restrict access to the WordPress admin area and any exposed endpoints through web application firewall rules if possible, although upgrading remains the only definitive solution given the nature of the flaw in the core plugin code. Regular security audits and monitoring for unusual activity on administrative endpoints can also help detect potential exploitation attempts while maintaining vigilance over system integrity.