CVE-2026-75845 in ArcadeDB
Summary
by MITRE • 08/18/2026
ArcadeDB versions 26.4.2 through 26.7.3 contain an authorization bypass vulnerability in the set_server_setting MCP server-level tool. SetServerSettingTool.execute() gates only on the global allowAdmin flag and never checks the caller's role, so in an MCP deployment with allowAdmin=true and a non-root allowedUsers set, any authenticated read-only user can invoke set_server_setting to modify server GlobalConfiguration, enabling configuration tampering or denial of service. The issue is fixed in 26.8.1.
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Analysis
by VulDB Data Team • 08/18/2026
ArcadeDB versions ranging from 26.4.2 through 26.7.3 are affected by a critical authorization bypass vulnerability within the set_server_setting tool, which operates at the Model Context Protocol server level. This flaw stems from an insufficient access control mechanism in the SetServerSettingTool.execute method, where security enforcement relies exclusively on a global allowAdmin flag rather than evaluating the specific role or permissions of the invoking user. In deployment configurations where allowAdmin is enabled and a restricted set of allowedUsers includes non-root accounts with read-only privileges, this architectural oversight allows any authenticated user possessing even minimal access rights to execute administrative configuration changes. The vulnerability effectively neutralizes the intended separation between standard operational users and system administrators, creating a significant security gap that undermines the integrity of the database server's global configuration settings.
The technical root cause lies in the logic governing privilege escalation within the MCP tool implementation. By failing to verify whether the caller holds an administrative role or specific write permissions for server-level parameters, the application accepts requests from unauthorized principals as valid administrative actions. This misconfiguration permits attackers who have successfully authenticated with low-privilege credentials to modify critical GlobalConfiguration values. Such modifications can lead to severe operational impacts, including configuration tampering that alters database behavior in unintended ways, potential denial of service through destabilizing system parameters, or the creation of backdoors by changing authentication and network settings. The absence of role-based checks means that the principle of least privilege is violated, allowing lateral movement within the administrative scope without requiring higher-level credentials.
This vulnerability aligns with CWE-269, which classifies Improper Privilege Management, specifically highlighting cases where software does not properly assign privileged functions to authorized actors. From a tactical perspective, this flaw facilitates unauthorized configuration changes that can be leveraged for persistence or disruption, mapping closely to ATT&CK techniques related to Defense Evasion and Impact through system manipulation. The ability of read-only users to alter server settings represents a significant escalation of privilege that compromises the confidentiality, integrity, and availability of the ArcadeDB instance. Organizations relying on these versions face substantial risk if their deployment models do not strictly isolate administrative interfaces from general user access or enforce strict role-based access controls at the application layer rather than relying solely on global flags.
To mitigate this vulnerability, immediate action is required to upgrade all affected instances to version 26.8.1, which contains the necessary patches to correct the authorization logic in SetServerSettingTool.execute(). Until an upgrade can be performed, administrators should consider network-level restrictions to limit access to MCP endpoints or disable the set_server_setting tool entirely if it is not strictly required for operational workflows. Additionally, reviewing and tightening role-based permissions within the application layer ensures that administrative functions are gated by explicit user roles rather than global configuration flags alone. Implementing robust input validation and enforcing strict adherence to least-privilege principles across all server-level tools will prevent similar authorization bypasses in future deployments. Regular security audits of authentication and authorization mechanisms are essential to maintain a secure posture against privilege escalation attacks targeting database management systems.