High-Severity Unrestricted File Upload in Langflow AI

The National Vulnerability Database has disclosed CVE-2026-6596, a high-severity (CVSS 7.3) unrestricted file upload vulnerability impacting Langflow AI’s langflow product, specifically versions up to 1.1.0. The flaw resides in the create_upload_file function within src/backend/base/Langflow/api/v1/endpoints.py, allowing remote attackers to upload arbitrary files.

This is a critical issue. Unrestricted file uploads are a classic attack vector, often leading to remote code execution (RCE) if an attacker can upload a malicious script and then trigger its execution. The National Vulnerability Database notes that an exploit has been publicly released, escalating the immediate risk for unpatched instances. The vendor, Langflow AI, reportedly did not respond to initial disclosure attempts.

For defenders, this means a straightforward path for attackers to compromise systems running vulnerable Langflow instances. The lack of vendor response to early disclosure is concerning and puts the onus squarely on users to identify and mitigate this risk proactively. Attackers will undoubtedly leverage the public exploit to gain initial access, pivot, and establish persistence.