Remote Code Execution in Langflow Prior to 1.9.2

Executive Summary

CVE-2026-48519 is a critical unauthenticated Remote Code Execution (RCE) vulnerability in Langflow versions 1.9.1 and earlier.

The vulnerability exists in the "Shareable Playground" feature, which allows anyone with a public flow link to execute workflows without authentication.

Specifically, attackers can inject arbitrary Python code by manipulating the field data.nodes[X].data.node.template.code.value in the JSON payload sent to the /api/v1/build_public_tmp/<flow-id>/flow endpoint.

This flaw enables execution of malicious code remotely, potentially leading to full system compromise.

The vulnerability is fixed in Langflow version 1.9.2 and later.

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Compliance Impact

The vulnerability allows unauthenticated remote code execution, which can lead to full system compromise affecting confidentiality, integrity, and availability of data.

Such a compromise can result in unauthorized access to sensitive personal or protected health information, potentially violating compliance requirements under standards like GDPR and HIPAA.

Therefore, this vulnerability poses a significant risk to maintaining compliance with these regulations due to the potential exposure and manipulation of sensitive data.

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Impact Analysis

This vulnerability can have severe impacts including unauthorized remote code execution on your system.

An attacker can execute arbitrary Python code without any privileges or authentication, potentially leading to full system compromise.

The impacts cover confidentiality, integrity, and availability of the affected system.

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Detection Guidance

This vulnerability can be detected by monitoring network traffic for requests to the endpoint /api/v1/build_public_tmp/<flow-id>/flow, especially those containing JSON payloads with the field data.nodes[X].data.node.template.code.value.

Commands to detect potential exploitation attempts could include using network monitoring tools like tcpdump or Wireshark to filter HTTP POST requests to the vulnerable endpoint.

• tcpdump -A -s 0 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | grep '/api/v1/build_public_tmp'
• Use curl or similar tools to test if the endpoint is accessible and vulnerable by sending crafted JSON payloads targeting data.nodes[X].data.node.template.code.value (only in a controlled, safe environment).

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Mitigation Strategies

The immediate mitigation step is to upgrade Langflow to version 1.9.2 or later, where this critical Remote Code Execution vulnerability has been fixed.

Until the upgrade can be performed, restrict access to the /api/v1/build_public_tmp endpoint to trusted users or networks to prevent unauthenticated exploitation.

Additionally, monitor logs and network traffic for suspicious activity targeting this endpoint and consider disabling the Shareable Playground feature if possible.

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