CVE-2026-33017

Critical9.8Published on March 20, 2026

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.

Actively exploited

  • In the CISA exploited-vulnerabilities catalogue since Mar 25, 2026
  • US federal agencies must remediate it by Apr 8, 2026 (BOD 22-01)
  • Attacked 1 day before the vulnerability was made public

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Source: CISA KEV · Sep 8, 2026 Sep 3, 2026 Aug 28, 2026 Aug 27, 2026 Aug 14, 2026 Jul 30, 2026

CVSS score9.8 / 10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness type (CWE)CWE-94, CWE-95, CWE-306
Vendorslangflow

Affected products

VendorsProductVersions
langflowlangflow< 1.8.2

Related articles

This product uses the NVD API but is not endorsed or certified by the NVD.

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