CVE-2026-39417 Details
Description
MaxKB is an open-source AI assistant for enterprise. Versions 2.7.1 and below contain an incomplete fix for CVE-2025-53928, where a Remote Code Execution vulnerability still exists in the MCP node of the workflow engine. MaxKB only restricts the referencing code path (loading MCP config from the database). The else branch, responsible for loading mcp_servers directly from user-supplied JSON remains completely unpatched. Since mcp_source is an optional field (required=False), an attacker can simply omit it or set it to any non-referencing value to bypass the fix. By calling the workflow creation API directly with a crafted JSON payload, an attacker can inject a complete MCP node configuration with stdio transport, arbitrary command, and args — achieving RCE when the workflow is triggered via chat. This issue has been fixed in version 2.8.0.
A remote code execution vulnerability has been identified in MaxKB versions 2.7.1 and prior. This issue arises from an incomplete fix for a previous vulnerability, allowing for command injection through the MCP node of the workflow engine. The vulnerability exists because the application only restricts the loading of MCP configuration from the database, while the alternative method of loading MCP servers from user-supplied JSON remains unpatched. Attackers can exploit this by omitting the 'mcp_source' field or setting it to a non-referencing value, thereby injecting a crafted MCP node configuration that includes arbitrary commands and arguments. When the modified workflow is executed via chat, the injected commands are executed, leading to remote code execution.
Users can upgrade to MaxKB version 2.8.0 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Apr 14, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-20 | Improper Input Validation | [email protected] |
| CWE-78 | Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| maxkb maxkb | < 2.8.0 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Apr 20, 2026 | Initial Analysis | [email protected] |
| Apr 14, 2026 | New CVE Received | [email protected] |