CVE-2026-96384 in Mermaid Diagram Field Module
Summary
by MITRE • 10/22/2026
Incorrect Authorization vulnerability in Drupal Mermaid Diagram Field allows Forceful Browsing. This issue affects Mermaid Diagram Field versions: from 1.0.4 to 1.0.9.
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Analysis
by VulDB Data Team • 10/22/2026
The identified security flaw resides within the Drupal module known as Mermaid Diagram Field, specifically impacting version ranges from 1.0.4 through 1.0.9. This vulnerability is classified under the category of Incorrect Authorization, which fundamentally represents a failure in access control mechanisms to properly restrict user interactions with system resources based on their assigned privileges or authentication status. In this specific context, the flaw manifests as Forceful Browsing, also commonly referred to as direct object reference manipulation when applied to web applications. The core technical issue stems from an insufficient verification of permissions before rendering or serving content associated with Mermaid diagrams. When a user requests access to a diagram field instance, the application fails to adequately validate whether the requesting entity possesses the necessary rights to view that specific resource. This oversight allows any authenticated user, and potentially unauthenticated users depending on the broader site configuration, to bypass intended restrictions and access data or functionality reserved for higher-privileged roles such as administrators or content editors.
From a technical perspective, this vulnerability exploits the lack of server-side authorization checks during the request processing lifecycle. When a HTTP GET request is directed at an endpoint handling Mermaid diagram fields, the application logic retrieves the requested object without cross-referencing it against the user's permission matrix defined by Drupal’s role-based access control system. Consequently, attackers can manipulate URL parameters or direct references to point toward resources they are not authorized to see. This type of flaw is critical because it undermines the integrity of the confidentiality controls implemented at the application layer. The absence of these checks means that sensitive configuration data, private content, or internal structural information embedded within diagram fields becomes accessible to unauthorized parties. Such exposure can lead to further exploitation vectors where attackers use gathered intelligence to craft more targeted attacks against the Drupal instance and its underlying infrastructure.
The operational impact of this vulnerability is significant for organizations relying on Drupal for content management with integrated visualization tools. Unauthorized access to Mermaid Diagram Field data may expose sensitive business logic, internal workflows, or proprietary information encoded within diagrams that were intended for restricted audiences. Beyond immediate data leakage, the ability to force browse these resources can facilitate reconnaissance activities where attackers map out the application’s structure and identify additional weak points. This aligns with common attack patterns observed in real-world scenarios where initial access is gained through simple enumeration of accessible objects rather than complex exploitation techniques. The ease of exploiting this flaw means that automated scanning tools could rapidly discover affected instances, increasing the risk of widespread compromise across multiple deployments if patches are not applied promptly.
To mitigate this vulnerability, immediate action should be taken to upgrade the Mermaid Diagram Field module to a version later than 1.0.9 where these authorization checks have been corrected. Developers and site administrators must ensure that all dependencies within their Drupal environment are updated to maintain consistency in security posture. In addition to patching, it is advisable to implement defense-in-depth strategies such as web application firewalls configured to detect anomalous access patterns indicative of forceful browsing attempts. Regular audits of role permissions and content visibility settings should also be conducted to ensure that no other modules or custom code introduce similar authorization gaps. Monitoring logs for unusual requests targeting diagram field endpoints can provide early warning signs of exploitation attempts, allowing security teams to respond before significant damage occurs.
This vulnerability is categorized under CWE-284 Improper Access Control within the Common Weakness Enumeration standard, which highlights failures in enforcing intended access restrictions. Furthermore, it maps to ATT&CK technique T1078 Valid Accounts and potentially T1539 Steal Web Session Cookie if session hijacking were involved, though primarily it reflects a failure in authorization logic rather than authentication bypass. Understanding these mappings helps security professionals contextualize the risk within broader threat landscapes and prioritize remediation efforts accordingly. By addressing this flaw, organizations can restore proper access control boundaries and prevent unauthorized entities from accessing sensitive diagrammatic data stored or processed by the Drupal platform.