CVE-2026-33017
Description
Langflow is a tool for building and deploying AI-powered agents and workflows. In versions prior to 1.9.0, the POST /api/v1/build_public_tmp/{flow_id}/flow endpoint allows building public flows without requiring authentication. When the optional data parameter is supplied, the endpoint uses attacker-controlled flow data (containing arbitrary Python code in node definitions) instead of the stored flow data from the database. This code is passed to exec() with zero sandboxing, resulting in unauthenticated remote code execution. This is distinct from CVE-2025-3248, which fixed /api/v1/validate/code by adding authentication. The build_public_tmp endpoint is designed to be unauthenticated (for public flows) but incorrectly accepts attacker-supplied flow data containing arbitrary executable code. This issue has been fixed in version 1.9.0.
Summary dbcve.org
Langflow versions before 1.9.0 contain an unauthenticated remote code execution vulnerability in the POST /api/v1/build_public_tmp/{flow_id}/flow endpoint. When the optional data parameter is supplied, attacker-controlled flow data containing arbitrary Python code in node definitions is passed to the exec() function without any sandboxing, allowing complete system compromise.
Mitigation
Upgrade to Langflow version 1.9.0 or later. If immediate upgrading is not possible, network-level restrictions on the affected endpoint should be implemented as a temporary measure.