CVE-2026-0771: Langflow PythonFunction RCE Vulnerability

CVE-2026-0771 Overview

CVE-2026-0771 is a code injection vulnerability affecting Langflow, a popular platform for building AI workflows. This vulnerability allows remote attackers to execute arbitrary code on affected installations by exploiting improper handling of Python function components within workflows. The attack vectors and exploitability will vary depending on the specific configuration of the product deployment.

The vulnerability exists within the handling of Python function components. Depending on product configuration, an attacker may be able to introduce custom Python code into a workflow, which is then executed by the application. An attacker can leverage this vulnerability to execute code in the context of the application, potentially leading to full system compromise.

Critical Impact

Remote code execution through malicious Python code injection in Langflow workflows, enabling attackers to execute arbitrary commands in the application context.

Affected Products

• Langflow (specific affected versions not disclosed)

Discovery Timeline

• January 23, 2026 - CVE-2026-0771 published to NVD
• January 26, 2026 - Last updated in NVD database

Technical Details for CVE-2026-0771

Vulnerability Analysis

This vulnerability is classified as CWE-94 (Improper Control of Generation of Code, also known as Code Injection). The flaw allows attackers to inject and execute arbitrary Python code through the PythonFunction component handling mechanism in Langflow.

The vulnerability requires network access and authenticated access to the Langflow instance. User interaction is also required for successful exploitation. Despite these prerequisites, the potential impact is significant—successful exploitation grants attackers full control over confidentiality, integrity, and availability of the affected system.

The vulnerability was reported through the Zero Day Initiative program as ZDI-CAN-27497 and assigned the advisory identifier ZDI-26-037.

Root Cause

The root cause of CVE-2026-0771 lies in insufficient input validation and sanitization when processing Python function components within Langflow workflows. The application fails to properly restrict or sandbox the execution of user-supplied Python code, allowing malicious code to be executed with the privileges of the application process.

When users define or modify Python function components in workflows, the application does not adequately validate or isolate the code being executed, creating an avenue for code injection attacks.

Attack Vector

The attack vector for this vulnerability is network-based, requiring authenticated access to a Langflow installation. An attacker with valid credentials or access to the workflow builder functionality can craft malicious Python code within a PythonFunction component.

The exploitation process involves injecting arbitrary Python code into a workflow component. When the workflow containing the malicious component is executed, the injected code runs in the context of the Langflow application, potentially allowing the attacker to read sensitive data, modify system configurations, install backdoors, or pivot to other systems on the network.

The specific exploitation method involves crafting malicious input within Python function components that bypass any existing sanitization measures. For detailed technical analysis, refer to the Zero Day Initiative advisory ZDI-26-037.

Detection Methods for CVE-2026-0771

Indicators of Compromise

• Unusual Python code patterns within Langflow workflow definitions, particularly in PythonFunction components
• Unexpected outbound network connections originating from the Langflow application process
• Anomalous system calls or child processes spawned by the Langflow service
• Suspicious modifications to workflow configurations by unauthorized or unexpected users

Detection Strategies

• Monitor Langflow application logs for unusual workflow modifications or execution patterns
• Implement code review processes for any Python functions added to workflows
• Deploy endpoint detection and response (EDR) solutions to identify suspicious process behavior from the Langflow service
• Use web application firewalls (WAF) to detect and block potential code injection attempts in API requests

Monitoring Recommendations

• Enable verbose logging for workflow creation and modification events
• Monitor for unusual authentication patterns or access to workflow builder functionality
• Implement real-time alerting for any processes spawned by the Langflow application
• Review audit logs for unexpected changes to PythonFunction components

How to Mitigate CVE-2026-0771

Immediate Actions Required

• Restrict access to Langflow workflow builder functionality to trusted users only
• Implement network segmentation to isolate Langflow instances from critical systems
• Review and audit all existing workflows for suspicious Python code in function components
• Consider temporarily disabling PythonFunction component creation until patches are applied

Patch Information

Organizations should monitor the official Langflow project and the Zero Day Initiative advisory ZDI-26-037 for patch availability and updated remediation guidance. Apply security patches as soon as they become available from the vendor.

Workarounds

• Implement strict access controls limiting who can create or modify workflows containing Python function components
• Deploy application-level sandboxing to isolate code execution within workflows
• Use network-level controls to restrict outbound connections from the Langflow application
• Enable enhanced logging and monitoring for all workflow execution activities

# Configuration example - Restrict Langflow access to trusted networks only
# Example iptables rules to limit access to Langflow service
iptables -A INPUT -p tcp --dport 7860 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 7860 -j DROP