CVE-2026-39417
MaxKB: RCE via MCP stdio command injection in workflow engine
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
4.6
MaxKB: RCE via MCP stdio command injection in workflow engine
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.
- Record
CVE-2026-39417- CVSS 3.1
- 4.6 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:L - Weakness
- CWE-78, CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2026-22162
4.6
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.
- Record
EUVD-2026-22162- CVSS 3.1
- 4.6 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:L - Updated
- 2026-11-02
NVD
4.6
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.
- Record
CVE-2026-39417- CVSS 3.1
- 4.6 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:L - CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L - Weakness
- CWE-20, CWE-78
- Updated
- 2026-11-02
OSV
4.6
MaxKB: RCE via MCP stdio command injection in workflow engine
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.
- Record
CVE-2026-39417- CVSS 3.1
- 4.6 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:L - Weakness
- CWE-20, CWE-78
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-39417 is a medium vulnerability (CVSS 4.6) in 1panel-dev Maxkb, published April 14, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.24%, the 15th percentile. No source names a fixed version.
References
github.com/1Panel-dev/MaxKB/security/advisories/GHSA-pw52-326g-r5xj
github.com/1Panel-dev/MaxKB/commit/50e96002ee5dca34c68d3d9333b64ea358c92304
github.com/1Panel-dev/MaxKB/releases/tag/v2.8.0
github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39417.json
nvd.nist.gov/vuln/detail/CVE-2026-39417