CVE-2026-40784
Published: 15 April 2026
Summary
CVE-2026-40784 is a high-severity Authorization Bypass Through User-Controlled Key (CWE-639) vulnerability. Its CVSS base score is 8.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 6.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 AC-3 (Access Enforcement) and SI-10 (Information Input Validation).
Deeper analysis
CVE-2026-40784 is an Authorization Bypass Through User-Controlled Key vulnerability (CWE-639) in the FluentBoards (fluent-boards) WordPress plugin developed by Mahmudul Hasan Arif. The flaw allows exploitation of incorrectly configured access control security levels and affects all versions from n/a through 1.91.2. It has a CVSS v3.1 base score of 8.1 (AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:L), indicating high severity due to network accessibility and significant confidentiality impact.
Unauthenticated attackers can exploit this vulnerability remotely without user interaction, though it requires high attack complexity. Exploitation enables scope change, granting high confidentiality access to sensitive data, low-level integrity modifications, and low availability disruption.
The Patchstack advisory details this as an insecure direct object references (IDOR) vulnerability specifically in the FluentBoards WordPress plugin version 1.91.2.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-22907
Vulnerability details
Authorization Bypass Through User-Controlled Key vulnerability in Mahmudul Hasan Arif FluentBoards fluent-boards allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects FluentBoards: from n/a through <= 1.91.2.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The vulnerability is an IDOR authorization bypass in a public-facing WordPress plugin allowing unauthenticated remote access to sensitive data, directly enabling exploitation of public-facing applications.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Enforces approved authorizations for access to system resources, directly preventing authorization bypass via user-controlled keys in IDOR vulnerabilities like this CVE.
Validates user-controlled inputs such as keys before using them in access decisions, blocking exploitation of insecure direct object references.
Limits privileges to the minimum necessary, reducing the scope and impact of unauthorized access gained through flawed access control configurations.