GHSA-qrpv-q767-xqq2

Опубликовано: 19 июн. 2026

Источник: github

Github: Прошло ревью

CVSS3: 8.4

Описание

Langflow: IDOR Vulnerability in /api/v1/responses Endpoint Allows Authenticated Attackers to Access Another User's Flow

Summary

Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request.

Details

The vulnerability exists in the get_flow_by_id_or_endpoint_name helper function in src/backend/base/langflow/helpers/flow.py (lines 399-414).

When a flow is accessed via UUID (flow_id), the function queries the database directly without verifying if the authenticated user owns that flow:

# src/backend/base/langflow/helpers/flow.py:399-414 async def get_flow_by_id_or_endpoint_name(flow_id_or_name: str, user_id: str | UUID | None = None) -> FlowRead: async with session_scope() as session: try: flow_id = UUID(flow_id_or_name) # When using UUID, query directly WITHOUT checking user_id flow = await session.get(Flow, flow_id) # ❌ No user_id check! except ValueError: endpoint_name = flow_id_or_name stmt = select(Flow).where(Flow.endpoint_name == endpoint_name) # Only when using endpoint_name is user_id checked if user_id: stmt = stmt.where(Flow.user_id == uuid_user_id)

This function is used by the /api/v1/responses endpoint (defined in src/backend/base/langflow/api/v1/openai_responses.py:589).

PoC (Proof of Concept)

# Attacker (user A) with API_KEY_A tries to execute victim (user B)'s flow curl -X POST "http://localhost:7860/api/v1/responses" \ -H "x-api-key: sk-ATTACKER_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "model": "VICTIM_FLOW_ID", "input_value": "test", "stream": false }' # Returns 200 and executes the victim's flow

Impact

Any authenticated user can:

Execute any flow in the system by knowing its flow ID
Access potentially sensitive data processed by victim's flows
Consume victim's resources

Fixes

Fixed in PR #12832 (fix(security): close IDOR in get_flow_by_id_or_endpoint_name), merged 2026-04-22, released in Langflow 1.9.1.

The helper normalizes user_id once and enforces ownership on both lookup branches (UUID and endpoint_name):

flow_id = UUID(flow_id_or_name) flow = await session.get(Flow, flow_id) if flow is not None and uuid_user_id is not None and flow.user_id != uuid_user_id: flow = None # cross-user lookup falls through to the shared 404

Key points:

Cross-user lookups return 404 (not 403), so flow existence is not disclosed via a 403-vs-404 oracle.
/api/v1/responses and /api/v2/workflow pass user_id explicitly, so fixing the helper closes them directly; the /api/v1/run* routes were additionally moved from a bare Depends(get_flow_by_id_or_endpoint_name) to auth-aware wrapper dependencies (defense in depth).
A malformed user_id now fails closed (404 instead of a raw 500).
Webhook routes intentionally keep the unscoped lookup (public by design / explicit ownership check elsewhere).
Regression tests cover the cross-user UUID case and reproduce the original PoC against /api/v1/responses.

Acknowledgements

Thanks to the security researchers who responsibly disclosed this vulnerability:

@yzeirnials
@johnatzeropath
@LeftenantZero
@Zwique

Ссылки

Пакеты

Наименование

langflow

pip

Затронутые версииВерсия исправления

< 1.9.1

1.9.1

EPSS

Процентиль: 57%

0.00887

Низкий

8.4 High

CVSS3

CVE ID

CVE-2026-55255

Дефекты

CWE-639

Связанные уязвимости

CVE-2026-55255

CVSS3: 8.4

nvd

3 месяца назад

Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request. This vulnerability is fixed in 1.9.1.

BDU:2026-10993

CVSS3: 8.4

fstec

3 месяца назад

Уязвимость функции get_flow_by_id_or_endpoint_name инструмента для создания и развёртывания агентов и рабочих процессов Langflow, позволяющая нарушителю обойти существующие ограничения безопасности

EPSS

Процентиль: 57%

0.00887

Низкий

8.4 High

CVSS3

CVE ID

CVE-2026-55255

Дефекты

CWE-639