CVE-2026-15939 in Simple Restrict Plugin
Summary
by MITRE • 08/02/2026
The Simple Restrict WordPress plugin before 1.2.9 does not enforce its content-restriction permission check on the REST API the way it does on the front end, relying there on a generic capability check instead of the Simple Restrict WordPress plugin before 1.2.9's own permission system, allowing users with contributor-level access or above to read the content of restricted posts and pages they were never granted access to.
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Analysis
by VulDB Data Team • 08/02/2026
The vulnerability in the Simple Restrict WordPress plugin affects versions prior to 1.2.9 and represents a critical access control flaw that undermines the plugin's core security mechanism. This issue stems from an inconsistent implementation of permission checks between the front-end user interface and the REST API endpoints. The plugin's intended functionality is to restrict content access based on specific user roles and capabilities, yet the REST API component fails to enforce these restrictions properly.
The technical flaw manifests as a capability check bypass that occurs exclusively within the REST API layer of the WordPress platform. While the front-end implementation correctly validates user permissions against the plugin's own access control system, the REST API endpoint relies on WordPress's generic capability checks instead of implementing the plugin-specific permission validation logic. This discrepancy creates a security gap where users with contributor-level access or higher can bypass content restrictions and retrieve protected posts and pages through direct API calls.
The operational impact of this vulnerability is significant for WordPress sites utilizing the Simple Restrict plugin, as it allows unauthorized information disclosure to users who should not have access to restricted content. Attackers with contributor privileges or higher can exploit this weakness to enumerate and access sensitive content that was intended to be hidden from them. This behavior violates fundamental security principles of least privilege and access control enforcement, potentially exposing confidential information, draft content, or restricted materials to unauthorized personnel.
The vulnerability aligns with CWE-284 (Improper Access Control) and represents a specific instance of inadequate authorization checking within API endpoints. From an attacker's perspective, this weakness maps to techniques described in the MITRE ATT&CK framework under T1078 (Valid Accounts) and T1566 (Phishing), as unauthorized users can leverage their existing contributor-level access to discover and retrieve restricted content through automated API requests. The issue particularly affects sites where content restriction is critical for maintaining confidentiality, such as those handling sensitive business information, personal data, or unpublished content.
Mitigation strategies should focus on immediate plugin updates to version 1.2.9 or later, which presumably addresses the inconsistent permission validation logic. Administrators should also implement additional monitoring of REST API access patterns to detect anomalous behavior that might indicate exploitation attempts. Network-level controls such as API rate limiting and IP whitelisting can provide additional defense in depth. Regular security audits of WordPress plugins should verify proper implementation of access control mechanisms, particularly for plugins handling sensitive content or user-specific restrictions. The incident underscores the importance of consistent security implementation across all application interfaces, including REST APIs, where the same security controls must be enforced regardless of the access method used by end users.