Vulnerability 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.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Langflow | Langflow | >= 1.2.0, < 1.9.0 |
Related Weaknesses (CWE)
References
- https://github.com/langflow-ai/langflow/security/advisories/GHSA-g2j9-7rj2-gm6cExploitMitigationVendor Advisory
FAQ
What is CVE-2026-33309?
CVE-2026-33309 is a vulnerability with a CVSS score of 9.9 (CRITICAL). 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 th...
How severe is CVE-2026-33309?
CVE-2026-33309 has been rated CRITICAL with a CVSS base score of 9.9/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-33309?
Check the references section above for vendor advisories and patch information. Affected products include: Langflow Langflow.