CVE-2026-16983 in Gutentor Plugin
Summary
by MITRE • 09/02/2026
The Gutentor WordPress plugin before 4.0.6 does not apply the correct context restriction to one of its REST endpoints, exposing the plaintext passwords of password-protected posts to any authenticated user with at least the Subscriber role.
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Analysis
by VulDB Data Team • 09/02/2026
The vulnerability identified in the Gutentor WordPress plugin prior to version 4.0.6 represents a critical failure in access control and data sanitization within the application's REST API implementation. This flaw specifically affects endpoints responsible for handling password-protected content, allowing authenticated users with even minimal privileges, such as the Subscriber role, to bypass intended security restrictions. In standard WordPress architecture, posts marked as password protected are designed to restrict visibility of their content until a valid password is provided by the user. The underlying mechanism typically involves encrypting or masking sensitive data on the server side and only decrypting it upon successful authentication via the frontend interface. However, due to insufficient context restriction in the REST API logic, this protective layer was effectively bypassed for specific endpoints exposed by the plugin.
From a technical perspective, the root cause lies in the improper validation of user capabilities against the data being requested through the REST endpoint. The developer failed to enforce strict capability checks that align with WordPress core security standards when serving content via JSON responses. Consequently, instead of returning an error or masked placeholder for password-protected posts, the API returned the full plaintext body and metadata associated with those protected items. This behavior violates the principle of least privilege, as it grants lower-level users access to data they should not be able to view even if authenticated. The absence of proper context restriction means that any user who can log into the WordPress site can exploit this endpoint programmatically or through standard browser requests to retrieve sensitive information without needing administrative rights or elevated permissions.
The operational impact of this vulnerability is significant, particularly for websites where password-protected content contains confidential business data, personal identifiable information, or proprietary assets. Since the exposure affects any authenticated user with at least a Subscriber role, which is often the default level assigned to new users in many WordPress installations, the blast radius is potentially large depending on the site's membership structure. Attackers can automate the enumeration of protected posts and extract their contents en masse, leading to unauthorized data disclosure. This scenario aligns directly with CWE-284, Improper Access Control, as it involves a failure to restrict access to resources based on user roles or authentication status. Furthermore, this vulnerability facilitates information leakage that could be leveraged for further attacks, such as social engineering campaigns using harvested sensitive details, which maps to the ATT&CK technique T1005, Data from Local System.
Mitigation strategies must prioritize immediate patching and rigorous review of REST API implementations in WordPress plugins. The primary remediation step is to upgrade the Gutentor plugin to version 4.0.6 or later, where this context restriction issue has been resolved by developers implementing proper capability checks before returning sensitive data via the API. For organizations unable to update immediately due to compatibility constraints, temporary workarounds include restricting access to the WordPress installation entirely for untrusted users and ensuring that only trusted administrators have accounts with any level of privilege. Additionally, security teams should audit other custom or third-party plugins for similar REST endpoint vulnerabilities by verifying that all data retrieval functions enforce strict role-based access control checks consistent with WordPress core standards. Regular vulnerability scanning focused on API endpoints can help detect such misconfigurations before they are exploited in the wild.