CVE-2026-41137: Flowise CSVAgent RCE Vulnerability

CVE-2026-41137 Overview

Flowise is a drag & drop user interface to build a customized large language model flow. A critical command injection vulnerability exists in the CSVAgent component of Flowise prior to version 3.1.0. The CSVAgent allows providing custom Pandas CSV read code, and due to lack of sanitization, an attacker can provide a command injection payload that will get interpolated and executed by the server. This vulnerability is classified as CWE-94 (Improper Control of Generation of Code - Code Injection).

Critical Impact

This command injection vulnerability allows authenticated attackers to execute arbitrary commands on the server hosting Flowise, potentially leading to complete system compromise, data exfiltration, and lateral movement within the network.

Affected Products

• Flowise versions prior to 3.1.0
• CSVAgent component with custom Pandas CSV read functionality
• Self-hosted Flowise deployments with exposed network interfaces

Discovery Timeline

• April 23, 2026 - CVE-2026-41137 published to NVD
• April 23, 2026 - Last updated in NVD database

Technical Details for CVE-2026-41137

Vulnerability Analysis

The vulnerability resides in the CSVAgent component of Flowise, which provides functionality for users to specify custom Pandas CSV read code. This feature is designed to allow flexibility in how CSV data is parsed and processed within LLM workflows. However, the implementation fails to properly sanitize user-supplied input before interpolating it into executable code.

When a user provides custom Pandas CSV read code to the CSVAgent, the input is directly interpolated into a code execution context without adequate validation or sanitization. This allows an attacker with access to the CSVAgent functionality to craft malicious payloads that escape the intended CSV parsing context and execute arbitrary system commands on the underlying server.

The attack requires low-privilege access to the Flowise interface, making it particularly dangerous in environments where multiple users have access to the platform or where the interface is exposed to untrusted networks.

Root Cause

The root cause of this vulnerability is improper input validation and insufficient sanitization of user-controlled data in the CSVAgent component. The custom Pandas CSV read code feature accepts arbitrary input that is then interpolated and executed by the Python interpreter on the server. Without proper escaping, sandboxing, or input validation, malicious code can be injected and executed with the privileges of the Flowise server process.

Attack Vector

This is a network-based attack vector that requires low-privilege authentication. An attacker with access to the Flowise interface can exploit this vulnerability by:

1. Accessing the CSVAgent component within a Flowise workflow
2. Providing malicious input in the custom Pandas CSV read code field
3. Crafting a payload that escapes the intended code context
4. The server interpolates and executes the malicious payload
5. Arbitrary commands are executed on the server with the privileges of the Flowise process

The attack does not require user interaction beyond the attacker's own actions, and successful exploitation can lead to complete server compromise. For detailed technical information, refer to the GitHub Security Advisory.

Detection Methods for CVE-2026-41137

Indicators of Compromise

• Unusual process spawning from the Flowise server process (e.g., shell commands, network utilities)
• Unexpected outbound network connections from the Flowise host
• Anomalous system calls or file system access patterns originating from the Flowise application
• Log entries showing suspicious CSVAgent inputs containing shell metacharacters or Python code injection patterns

Detection Strategies

• Monitor Flowise application logs for CSVAgent requests containing suspicious patterns such as os.system, subprocess, exec, eval, or shell metacharacters
• Implement network monitoring to detect unexpected outbound connections from Flowise servers
• Deploy endpoint detection solutions to identify anomalous process creation chains originating from the Flowise process
• Review audit logs for unusual file access or modification patterns on systems running Flowise

Monitoring Recommendations

• Enable verbose logging for the CSVAgent component to capture all user-supplied input
• Implement application-layer firewalls or WAFs to inspect and filter malicious payloads targeting the CSVAgent endpoint
• Deploy behavioral monitoring to baseline normal Flowise server activity and alert on deviations
• Configure SIEM rules to correlate Flowise access patterns with post-exploitation indicators

How to Mitigate CVE-2026-41137

Immediate Actions Required

• Upgrade Flowise to version 3.1.0 or later immediately
• If immediate upgrade is not possible, disable or restrict access to the CSVAgent component
• Review Flowise access controls and limit user permissions to trusted personnel only
• Audit logs for any evidence of exploitation attempts prior to patching

Patch Information

This vulnerability is fixed in Flowise version 3.1.0. Organizations should upgrade to this version or later to remediate the command injection vulnerability in the CSVAgent component. For additional details, see the GitHub Security Advisory.

Workarounds

• Restrict network access to Flowise deployments using firewall rules or network segmentation
• Implement strict access controls to limit who can access CSVAgent functionality
• Deploy a web application firewall (WAF) to filter malicious input patterns before they reach the application
• Consider running Flowise in a containerized environment with limited privileges to reduce the impact of successful exploitation

# Example: Restrict network access to Flowise
# Allow only trusted IP ranges to access Flowise port
iptables -A INPUT -p tcp --dport 3000 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 3000 -j DROP