Langflow · Langflow
CVE-2026-33017
Langflow has Unauthenticated Remote Code Execution via Public Flow Build Endpoint
What it is
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.
CISA: Langflow contains a code injection vulnerability that could allow building public flows without requiring authentication.
What to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Deadline for US federal agencies: April 8, 2026
More exploited flaws from Langflow
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Jul 21, 2026 | Inclusion of Functionality from Untrusted Control Sphere | Langflow | Critical 9.8 | 63% |
| Jul 7, 2026 | Authorization Bypass Through User-Controlled Key | Langflow | High 8.4 | 0.9% |
| May 21, 2026 | Origin Validation Error | Langflow | Critical 9.4 | 93% |
| May 5, 2025 | Missing Authentication | Langflow | Critical 9.8 | >99.9% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.