Critical Langflow Flaw CVE-2026-33017 Triggers Attacks within 20 Hours of Disclosure

A critical unauthenticated remote code execution vulnerability (CVE-2026-33017, CVSS 9.3) in Langflow was actively exploited within 20 hours of public disclosure.

• •The flaw in the POST /api/v1/build_public_tmp/{flow_id}/flow endpoint allows attackers to inject arbitrary Python code executed via exec() with no authentication required.
• •All Langflow versions up to and including 1.8.1 are affected; a partial fix exists in development version 1.9.0.dev8.
• •Attackers built working exploits directly from the advisory with no public PoC, harvesting credentials, environment variables, and .env file contents.
• •Threat actors moved from automated scanning to custom Python scripts, delivering next-stage payloads from a remote IP address.
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