What’s Vulnerable › Vulnerabilities
CVE-2026-33309: Langflow has an Arbitrary File Write (RCE) via v2 API
- Severity: critical (CVSS 9.9 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 13.5% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2026-03-24 · updated 2026-06-17
- Weakness: CWE-22
Description
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.
Affected products
- IBM Langflow OSS: from 1.2.0 before 1.9.0 — fixed in 1.9.0
How to fix
Upgrade to a fixed version: IBM Langflow OSS 1.9.0. Check the vendor advisory for mitigations.
References
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