GHSA-5xvg-pmgg-3mxr: Flowise: CSV Agent Prompt Injection Remote Code Execution Vulnerability

-- ABSTRACT ------------------------------------- Trend Micro's Zero Day Initiative has identified a vulnerability affecting the following products: Flowise - Flowise -- VULNERABILITY DETAILS ------------------------ - Version tested: 3.1.1 - Installer file: https://github.com/FlowiseAI/Flowise (npm install flowise@3.1.1) - Platform tested: Ubuntu 25.10 A prompt injection sent to a chatflow using a CSV Agent node can cause the LLM to respond with a malicious Python script that bypasses the blocklist validator and executes in an unsandboxed pyodide environment. An attacker can leverage this to execute arbitrary code in the context of the user running the server. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Flowise. Authentication is not required to exploit this vulnerability. The specific flaw exists within the run method of the CSV_Agents class. The issue results from insufficient input sanitization when using untrusted data to construct an LLM prompt. An attacker can leverage this vulnerability to execute code in the context of the service account. Analysis When a user makes a query against a chatflow using the CSV Agent node, the run method of the CSV_Agents class is called. This method reads the CSV file, loads a pyodide environment, and uses pandas to extract column names and data types into a dictionary. It then constructs a system prompt using that dictionary and the user's input, and sends this prompt to a configured LLM. The LLM response is stored in a variable named pythonCode. The method then attempts to validate this value using validatePythonCodeForDataFrame from packages/components/src/pythonCodeValidator.ts before evaluating it in pyodide. The validator relies on a static regex blocklist. It can be bypassed using obfuscation techniques including string concatenation to reconstruct forbidden identifiers, chr() encoding, aliasing of dangerous builtins, getattribute with concatenated attribute n