CVE-2026-3999 in ID Server
Summary
by MITRE • 03/13/2026
A broken access control may allow an authenticated user to perform a horizontal privilege escalation. The vulnerability only impacts specific configurations.
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Analysis
by VulDB Data Team • 06/08/2026
This vulnerability represents a critical access control flaw that enables authenticated users to escalate their privileges horizontally within a system. The issue manifests as a broken access control condition where users can potentially access resources or perform actions typically restricted to other users within the same privilege level. The vulnerability specifically affects certain system configurations, indicating that the flaw may be dependent on particular implementation details or deployment scenarios. According to CWE standards, this vulnerability maps to CWE-285 which encompasses improper authorization issues, and more specifically CWE-284 which addresses insufficient access control. The horizontal privilege escalation capability means that an attacker who has gained initial access through legitimate authentication can leverage this flaw to access other users' data or perform operations within their scope without proper authorization.
The technical implementation of this vulnerability likely involves insufficient validation of user permissions or roles during access requests. This could occur in scenarios where the system fails to properly verify that a user's request aligns with their assigned privileges or when the access control mechanisms do not adequately enforce boundaries between user sessions or data contexts. The impact is particularly concerning because it allows authenticated users to bypass normal access controls that should prevent them from accessing other users' resources. This type of vulnerability is often found in web applications where session management or role-based access controls are improperly implemented, allowing users to manipulate access tokens, session identifiers, or request parameters to gain unauthorized access to other users' data or functionality.
The operational implications of this vulnerability extend beyond simple data exposure, potentially enabling broader system compromise through information disclosure, data manipulation, or denial of service attacks. Attackers could exploit this flaw to access sensitive user information, modify other users' accounts, or perform unauthorized transactions within the system. The fact that this vulnerability only impacts specific configurations suggests that it may be related to particular database schemas, application frameworks, or middleware implementations that fail to properly enforce access boundaries. Organizations with affected systems may experience significant security breaches, regulatory compliance issues, and potential legal ramifications from unauthorized data access. The vulnerability aligns with attack patterns documented in the MITRE ATT&CK framework under privilege escalation techniques, specifically targeting the horizontal movement phase where adversaries attempt to access resources within the same privilege level.
Mitigation strategies should focus on implementing robust access control mechanisms that properly validate user permissions for every request. Organizations should ensure that all access control decisions are made at the application level with proper authorization checks, rather than relying on client-side validation or URL-based access control. Implementing the principle of least privilege, where users only have access to resources necessary for their role, can significantly reduce the impact of such vulnerabilities. Regular security testing including penetration testing and access control reviews should be conducted to identify and remediate similar issues. The implementation of proper session management, including secure session tokens and automatic session invalidation, can help prevent unauthorized access. Additionally, organizations should consider implementing security monitoring and logging to detect unusual access patterns that might indicate exploitation attempts. The vulnerability requires careful attention to configuration management and regular updates to ensure that access control mechanisms are properly enforced across all system components and configurations.