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Description

Flowise before 3.0.6 (affected versions 2.2.7-patch.1 and earlier) contains an unsandboxed remote code execution vulnerability in the Custom MCP feature, which is designed to execute OS commands such as launching local MCP servers. Because Flowise's authentication and authorization model is minimal and lacks role-based access control, and the default installation runs without authentication unless FLOWISE_USERNAME and FLOWISE_PASSWORD are set, an attacker can send a crafted JSON payload with the header 'x-request-from: internal' to the /api/v1/node-load-method/customMCP endpoint to execute arbitrary OS commands, resulting in complete compromise of the platform container or server.

PUBLISHED Reserved 2026-06-20 | Published 2026-06-25 | Updated 2026-06-25 | Assigner VulnCheck




CRITICAL: 9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CRITICAL: 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Problem types

Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Product status

Default status
unaffected

Any version before 3.0.6
affected

3.0.6 (semver)
unaffected

Credits

assaf-levkovich-jf reporter

References

github.com/...lowise/security/advisories/GHSA-6933-jpx5-q87q (GitHub Security Advisory (GHSA-6933-jpx5-q87q)) vendor-advisory

www.vulncheck.com/...ed-remote-code-execution-via-custom-mcp (VulnCheck Advisory: Flowise - Unsandboxed Remote Code Execution via Custom MCP) third-party-advisory

cve.org (CVE-2025-71336)

nvd.nist.gov (CVE-2025-71336)

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