CVE-2026-111681 in EFAK
Summary
by MITRE • 10/16/2026
EFAK through 5.1.0 contains a missing authorization vulnerability that allows authenticated low-privilege users to manage accounts because the /api/users endpoints lack administrator role checks. Attackers can send POST, PUT, or DELETE requests to UserController to grant themselves ROLE_ADMIN, create administrators, or delete users, gaining control of managed Kafka clusters.
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Analysis
by VulDB Data Team • 10/17/2026
The vulnerability identified in EFAK versions through 5.1.0 represents a critical failure in access control mechanisms within the application's user management subsystem. Specifically, the endpoints located at /api/users fail to enforce proper authorization checks for administrative actions. This flaw allows authenticated users with low-privilege roles to perform operations that should be restricted exclusively to administrators. The core technical issue lies in the UserController implementation, which processes POST, PUT, and DELETE requests without verifying whether the requesting user possesses the necessary ROLE_ADMIN privileges before executing state-changing commands on other user accounts.
From a technical perspective, this is a classic case of Insecure Direct Object Reference combined with Broken Access Control. When an attacker sends a request to modify or delete a user account, the server accepts and processes it based solely on the presence of valid authentication credentials rather than validating the requester's permission level relative to the action being performed. This allows malicious actors to manipulate their own profile by sending PUT requests that alter their role attribute from standard USER to ROLE_ADMIN. Once elevated, they can create new administrative accounts or delete existing users, effectively bypassing all intended security boundaries within the application layer.
The operational impact of this vulnerability is severe and far-reaching given EFAK's integration with Apache Kafka clusters. By gaining administrator privileges through these endpoints, an attacker achieves full control over managed Kafka instances. This level of access enables the creation of unauthorized topics, modification of cluster configurations, deletion of critical data streams, or complete denial of service by removing essential user accounts required for cluster operation. The ability to escalate privileges arbitrarily undermines the integrity and availability of the entire messaging infrastructure supported by EFAK.
This vulnerability aligns with CWE-269 Improper Privilege Management and CWE-862 Missing Authorization within the Common Weakness Enumeration framework. In terms of adversary tactics, it corresponds to ATT&CK technique T1078 Valid Accounts, where attackers leverage legitimate credentials to gain unauthorized access, followed by T1078.003 Cloud Accounts if cloud-based deployments are involved, and potentially T1496 Resource Hijacking or T1529 System Shutdown/Defacement depending on the extent of cluster manipulation allowed through the compromised admin interface.
Mitigation strategies should prioritize immediate patching to version 5.1.1 or later where this issue has been resolved. In environments where upgrading is not immediately feasible, network-level controls such as Web Application Firewalls can be configured to restrict access to /api/users endpoints exclusively from trusted administrative IP ranges. Additionally, implementing strict server-side validation that verifies the requester's role against every state-changing operation before execution will prevent privilege escalation attempts. Regular auditing of user roles and enforcement of least-privilege principles across all API endpoints are essential for maintaining robust security posture in Kafka management environments.