Vulnerability details

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.

• https://github.com/langflow-ai/langflow/security/advisories/GHSA-vwmf-pq79-vjvx x_refsource_CONFIRM
• https://github.com/langflow-ai/langflow/commit/73b6612e3ef25fdae0a752d75b0fabd47328d4f0 x_refsource_MISC
• https://github.com/advisories/GHSA-rvqx-wpfh-mfx7 x_refsource_MISC
• https://www.sysdig.com/blog/cve-2026-33017-how-attackers-compromised-langflow-ai-pipelines-in-20-hours third-party-advisory
• https://medium.com/@aviral23/cve-2026-33017-how-i-found-an-unauthenticated-rce-in-langflow-by-reading-the-code-they-already-dc96cdce5896 exploit
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-33017 government-resource
• https://github.com/langflow-ai/langflow/releases/tag/1.8.2 patch