CVE-2026-33017
Langflow has Unauthenticated Remote Code Execution via Public Flow Build Endpoint
Description
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.
In plain language
AI Act nowLangflow has a public “build flow” feature that lets attackers run arbitrary code on your server without logging in—this is critical and should worry any small business running Langflow exposed to the internet.
CVE-2026-33017 is an unauthenticated remote code execution in Langflow’s public flow build endpoint, where specially crafted flow data is accepted and executed as Python on the server without sandboxing.
What to do now
- Check whether your Langflow server is reachable from the internet (especially the public flow build endpoint for building “public flows”).
- If Langflow is exposed, upgrade to a fixed version: Langflow fixed in 1.8.2.
- If you cannot upgrade right away, disable or block public flow building from untrusted networks until the upgrade is complete.
- After upgrading, review logs for requests to the public build flow endpoint and look for signs of unexpected code execution or unusual outbound connections.
CVSS Vector Breakdown
AV:NAttack VectorAC:LAttack ComplexityPR:NPrivileges RequiredUI:NUser InteractionS:UScopeC:HConfidentialityI:HIntegrityA:HAvailabilityWeaknesses
Affected Products
Exploitability
Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Attack Graph
Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.
MITRE ATT&CK
3 techniquesReferences
- Langflow RCE Exploited to Deploy Monero Miner on Exposed AI App Endpointsen·The Hacker News·
- 29th June – Threat Intelligence Reporten-us·Check Point Research·
- Critical Langflow Flaws Allow Unauthenticated Remote Code Executionen-us·Daily CyberSecurity (securityonline.info)·
- Path traversal flaw in AI dev platform Langflow exploited in attacksen-us·BleepingComputer· Summary only·
- Unpatched Langflow Flaw CVE-2026-5027 Exploited for Unauthenticated RCEen·The Hacker News·
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