CVE-2026-78466 in Fluent Boards Pro Plugin
Summary
by MITRE • 08/25/2026
The Fluent Boards Pro plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 2.0.11 due to missing validation on a user controlled key. This makes it possible for authenticated attackers, with Subscriber-level access and above, to perform an unauthorized action.
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Analysis
by VulDB Data Team • 09/06/2026
The Fluent Boards Pro plugin for WordPress contains a critical security flaw classified as an Insecure Direct Object Reference (IDOR), specifically identified under CWE-639 in the Common Weakness Enumeration standard. This vulnerability exists across all versions up to and including 2.0.11, stemming from insufficient validation of user-controlled input parameters within the application logic. The core technical issue arises because the software fails to verify that a requesting user has explicit authorization to access or manipulate specific data objects based on their provided identifiers. Instead of relying solely on session-based authentication tokens which confirm identity, the system trusts the direct object references passed by the client without cross-referencing them against the permissions associated with the authenticated account. This architectural oversight allows an attacker who possesses valid credentials at the Subscriber level or higher to bypass intended access controls and interact with resources belonging to other users or administrative functions that should remain restricted.
From a technical perspective, this vulnerability exploits the fundamental assumption in many web applications that if a user is logged in, they are authorized to perform actions on any object referenced by an ID provided in HTTP requests. In the context of Fluent Boards Pro, the application likely accepts parameters such as board IDs, task lists, or configuration keys directly from POST or GET requests without implementing proper ownership checks. An authenticated attacker can manipulate these identifiers to target resources outside their designated scope. For instance, if a user is assigned ID 100 and attempts to modify data associated with ID 200, the application processes this request because it does not validate that User 100 has permission over Resource 200. This lack of authorization enforcement effectively neutralizes the security boundary established by WordPress role management systems, allowing low-privilege users to escalate their influence within the plugin's ecosystem significantly beyond what is intended by the developer or site administrator.
The operational impact of this vulnerability is substantial for organizations relying on Fluent Boards Pro for project management and workflow automation. Since authenticated attackers with even minimal Subscriber-level access can perform unauthorized actions, they may be able to view sensitive project data, modify critical task statuses, delete important boards, or alter configurations that affect team collaboration. This compromises the confidentiality, integrity, and availability of project information managed through the platform. Furthermore, because WordPress plugins often integrate deeply with other site functionalities, an attacker could potentially chain this IDOR vulnerability with other weaknesses to achieve broader system compromise, such as data exfiltration or disruption of business operations dependent on accurate task tracking and resource allocation. The ability for low-privilege users to manipulate high-value objects undermines the trust model of collaborative platforms and exposes organizations to significant reputational and operational risks.
To mitigate this vulnerability, immediate action is required by upgrading Fluent Boards Pro to a version later than 2.0.11 where these access control checks have been implemented. Developers must ensure that all endpoints handling object references implement strict authorization logic, verifying that the authenticated user owns or has explicit permission for every resource they attempt to modify. This involves implementing server-side validation that maps user IDs to resource ownership records before processing any state-changing requests. Additionally, organizations should enforce principle of least privilege by ensuring users are assigned only the minimum roles necessary for their job functions, thereby limiting the potential blast radius if such vulnerabilities were present in other plugins. Regular security audits and penetration testing focusing on broken access control patterns aligned with MITRE ATT&CK techniques like T1078 Valid Accounts can help identify similar weaknesses across the WordPress ecosystem before they are exploited by malicious actors seeking to gain unauthorized footholds within corporate networks.