GHSA-f43r-cc68-gpx4

Suggest an improvement
Source
https://github.com/advisories/GHSA-f43r-cc68-gpx4
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/12/GHSA-f43r-cc68-gpx4/GHSA-f43r-cc68-gpx4.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-f43r-cc68-gpx4
Aliases
Published
2025-12-19T22:53:13Z
Modified
2026-06-06T00:45:48Z
Severity
  • 7.1 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L CVSS Calculator
Summary
External Control of File Name or Path in Langflow
Details

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

  1. 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:

  2. 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)]

  3. 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."""

  4. 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()

  5. 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

    image

  • 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"}'
    image

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.
Database specific 
{
    "cwe_ids":  [
        "CWE-610",
        "CWE-73"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2025-12-19T22:53:13Z",
    "nvd_published_at":  "2025-12-19T18:15:51Z",
    "severity":  "HIGH"
}
References

Affected packages

PyPI / langflow

Package

Name
langflow
View open source insights on deps.dev
Purl
pkg:pypi/langflow

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
1.7.1

Affected versions

0.*
0.0.31
0.0.32
0.0.33
0.0.40
0.0.44
0.0.45
0.0.46
0.0.52
0.0.53
0.0.54
0.0.55
0.0.56
0.0.57
0.0.58
0.0.61
0.0.62
0.0.63
0.0.64
0.0.65
0.0.66
0.0.67
0.0.68
0.0.69
0.0.70
0.0.71
0.0.72
0.0.73
0.0.74
0.0.75
0.0.76
0.0.78
0.0.79
0.0.80
0.0.81
0.0.83
0.0.84
0.0.85
0.0.86
0.0.87
0.0.88
0.0.89
0.1.0
0.1.2
0.1.3
0.1.4
0.1.5
0.1.6
0.1.7
0.2.0
0.2.1
0.2.2
0.2.3
0.2.4
0.2.5
0.2.6
0.2.7
0.2.8
0.2.9
0.2.10
0.2.11
0.2.12
0.2.13
0.3.0
0.3.1
0.3.2
0.3.3
0.3.4
0.4.0
0.4.1
0.4.2
0.4.3
0.4.4
0.4.5
0.4.6
0.4.7
0.4.8
0.4.9
0.4.10
0.4.11
0.4.12
0.4.14
0.4.15
0.4.16
0.4.17
0.4.18
0.4.19
0.4.20
0.4.21
0.5.0a0
0.5.0a1
0.5.0a2
0.5.0a3
0.5.0a4
0.5.0a5
0.5.0a6
0.5.0b0
0.5.0b2
0.5.0b3
0.5.0b4
0.5.0b5
0.5.0b6
0.5.0
0.5.1
0.5.2
0.5.3
0.5.4
0.5.5
0.5.6
0.5.7
0.5.8
0.5.9
0.5.10
0.5.11
0.5.12
0.6.0rc1
0.6.0
0.6.1
0.6.2
0.6.3a0
0.6.3a1
0.6.3a2
0.6.3a3
0.6.3a4
0.6.3a5
0.6.3a6
0.6.3a7
0.6.3
0.6.4a0
0.6.4a1
0.6.4
0.6.5a0
0.6.5a1
0.6.5a2
0.6.5a3
0.6.5a4
0.6.5a5
0.6.5a6
0.6.5a7
0.6.5a8
0.6.5a9
0.6.5a10
0.6.5a11
0.6.5a12
0.6.5a13
0.6.5
0.6.6
0.6.7a1
0.6.7a2
0.6.7a3
0.6.7a5
0.6.7
0.6.8
0.6.9
0.6.10
0.6.11
0.6.12
0.6.14
0.6.15
0.6.16
0.6.17
0.6.18
0.6.19
1.*
1.0.0a0
1.0.0a1
1.0.0a2
1.0.0a3
1.0.0a4
1.0.0a5
1.0.0a6
1.0.0a7
1.0.0a8
1.0.0a9
1.0.0a10
1.0.0a11
1.0.0a12
1.0.0a13
1.0.0a14
1.0.0a15
1.0.0a17
1.0.0a18
1.0.0a19
1.0.0a20
1.0.0a21
1.0.0a22
1.0.0a23
1.0.0a24
1.0.0a25
1.0.0a26
1.0.0a27
1.0.0a28
1.0.0a29
1.0.0a30
1.0.0a31
1.0.0a32
1.0.0a33
1.0.0a34
1.0.0a35
1.0.0a36
1.0.0a37
1.0.0a38
1.0.0a39
1.0.0a40
1.0.0a41
1.0.0a42
1.0.0a43
1.0.0a44
1.0.0a45
1.0.0a46
1.0.0a47
1.0.0a48
1.0.0a49
1.0.0a50
1.0.0a51
1.0.0a52
1.0.0a53
1.0.0a55
1.0.0a56
1.0.0a57
1.0.0a58
1.0.0a59
1.0.0a60
1.0.0a61
1.0.0rc0
1.0.0rc1
1.0.0
1.0.1
1.0.2
1.0.3
1.0.4
1.0.5
1.0.6
1.0.7
1.0.8
1.0.9
1.0.10
1.0.11
1.0.12
1.0.13
1.0.14
1.0.15
1.0.16
1.0.17
1.0.18
1.0.19
1.0.19.post1
1.0.19.post2
1.1.0
1.1.1
1.1.2
1.1.3
1.1.4
1.1.4.post1
1.2.0
1.3.0
1.3.1
1.3.2
1.3.3
1.3.4
1.4.0
1.4.1
1.4.2
1.4.3
1.5.0
1.5.0.post1
1.5.0.post2
1.5.1
1.6.0
1.6.1
1.6.2
1.6.3
1.6.4
1.6.5
1.6.6
1.6.7
1.6.8
1.6.9
1.7.0

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/12/GHSA-f43r-cc68-gpx4/GHSA-f43r-cc68-gpx4.json"