Langflow — Path Traversal (CVE-2026-33309)
Date: 2026-03
Affected: langflow/langflow
Attack vector: path-traversal
Category: vulnerability-disclosure
Severity: Critical
CVE: CVE-2026-33309
CWE: CWE-22
CWE-284
CWE-73
CWE-94
CVSS: 9.9 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H)

Langflow is a tool for building and deploying AI-powered agents and workflows. Versions 1.2.0 through 1.8.1 have a bypass of the patch for CVE-2025-68478 (External Control of File Name), leading to the root architectural issue within `LocalStorageService` remaining unresolved. Because the underlying storage layer lacks boundary containment checks, the system relies entirely on the HTTP-layer `ValidatedFileName` dependency. This defense-in-depth failure leaves the `POST /api/v2/files/` endpoint vulnerable to Arbitrary File Write. The multipart upload filename bypasses the path-parameter guard, allowing authenticated attackers to write files anywhere on the host system, leading to Remote Code Execution (RCE). Version 1.9.0 contains an updated fix.


Mitigations:

Architectural layers (MAESTRO):