Langflow: remote code execution

### Summary Langflow's built-in Python interpreter components , `PythonREPLComponent` (Python Interpreter) and the legacy `PythonREPLToolComponent` (Python REPL Tool) , executed arbitrary user- or model-supplied Python code inside flows without effective sandboxing. Because the code ran in-process with the privileges of the Langflow service, any **authenticated** user who could edit and run a flow could achieve remote code execution and, from there, escalate privileges to superuser (e.g. by opening a database session and flipping `is_superuser`) or compromise the host. **This issue is fixed as of 1.10.1**, with additional hardening through 1.12.3. See *Remediation* below. ### Affected - **Package:** `langflow` (PyPI), and the underlying `lfx` package that ships the component. - **Vulnerable versions:** `< 1.10.1`. - **Patched:** `1.10.1` (core fix). Upgrade to `>= 1.12.3` for the complete hardening series. ### Details The root cause is **code injection** (CWE-94/CWE-95): the component passed raw input to LangChain's `PythonREPL`, which is explicitly *not* a security sandbox. Two distinct weaknesses existed before 1.10.1: 1. **Unrestricted builtins (default deployments).** `get_globals()` built the `exec` globals from the `global_imports` allow-list but never set `__builtins__`. CPython's `exec()` then auto-injected the full `builtins` module, leaving `__import__`, `open`, `eval`, `exec` and the whole import machinery reachable regardless of the allow-list , e.g. `__import__("os").system(...)` or `__import__("subprocess").check_output([...])`. This made the "only modules in Global Imports can be used" guarantee false, and it applied even with the **default** configuration (`allow_custom_components=True`). 2. **No server-policy gate (locked-down deployments).** Even a deployment hardened with `allow_custom_components=False` could still run interpreter code, because the components did not consult that policy before executing. Both let an authenticated user run the reported PoC, which opens a DB session and sets `is_superuser = True` on their account, or writes to the filesystem / runs OS commands with the service's privileges. ### PoC (as reported) 1. Authenticate as a normal user. 2. Create a flow with the `PythonREPLComponent`. 3. Execute Python that imports Langflow internals and elevates the account: ```python import asyncio from sqlmodel import select from langflow.services.database.models.user.model import User from langflow.services.deps import session_scope async def escalate(): async with session_scope() as session: stmt = select(User).where(User.username == 'testuser') user = (await session.exec(stmt)).first() if user: user.is_superuser = True session.add(user) await session.commit() asyncio.run(escalate()) ``` ### Impact Any authenticated user could: - Execute arbitrary Python / OS commands with the Langflow service's privileges (RCE). - Escalate their own account to superuser via direct database access. - Read/modify data and configuration, and potentially pivot to the underlying host. ### Remediation Upgrade to **Langflow 1.10.1 or later** (preferably **>= 1.12.3**). The interpreter components were hardened with layered, defense-in-depth controls, applied in `run_python_repl()` before any code is executed: - **Restricted builtins** , `get_globals()` injects a curated `safe_builtins()` mapping, removing `__import__`, `eval`, `exec`, `compile`, `open`, `input`, `globals`/`locals`/`vars`, `getattr`/`setattr`, etc. (#13397) - **AST validation** , `validate_code_safety()` rejects inline `import`/`from ... import`, dunder/escape-gadget attribute access (`__class__`, `__subclasses__`, `__globals__`, frame/traceback introspection) and format-string dunder traversal. (#13397) - **Server-policy gate** , `ensure_code_execution_enabled()` refuses to run when `allow_custom_components=False` or `block_code_interpreter_components=True`, and **

CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Severity from

GitHub (reviewed advisory)

Weakness

CWE-266, CWE-94, CWE-95

Also known as

CVE-2026-10561

• github.com/langflow-ai/langflow/security/advisories/GHSA-8qpj-27x8-pwpq
• nvd.nist.gov/vuln/detail/CVE-2026-10561
• github.com/langflow-ai/langflow/pull/13700
• github.com/langflow-ai/langflow/commit/2754c84aad1306f463db1c3bbb3e8ffbe85da77d
• github.com/langflow-ai/langflow
• github.com/langflow-ai/langflow/releases/tag/v1.10.1
• www.ibm.com/support/pages/node/7277242