CVE-2026-33017: Langflow | defend.network

What is CVE-2026-33017?

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.

CVSS9.8 NVD 3.1

SeverityCRITICAL

Exploitation In the wild In CISA KEV

EPSS98% · P100

Triage statusActive Exploit

ActionPatch immediately

CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

NVD published2026-03-20

NVD last modified2026-06-17

Timeline

2026-03-20Published to the U.S. National Vulnerability Database (NVD)
2026-03-21First covered in a defend.network daily briefing
2026-03-25Added to the CISA Known Exploited Vulnerabilities (KEV) catalog
2026-04-08CISA federal remediation deadline (BOD 22-01)
2026-06-17NVD record last updated

CISA Known Exploited Vulnerability

Langflow Code Injection Vulnerability

Added to KEV2026-03-25

Federal patch deadline2026-04-08

Known ransomware useUnknown

Affected product

Langflow

Remediation Steps

Apply the vendor security update for Langflow as a priority.
Restrict network exposure of the affected service to trusted sources until patched.
Review logs and detections for indicators of exploitation.
Confirm fixed versions against the official vendor advisory before deploying.

References

Referenced in our briefings & reports

Vulnerability Priority Report – Week 5 of June 2026 (June 29 – July 5)
AI agent poisoning, Langflow RCE exploited: Microsoft warns data theft risks (2026-07-01)
Chinese APT in telecom backbone; Langflow zero-day exploited (2026-03-27)
Oracle Identity Manager, Langflow exploited; Trivy supply-chain worm (2026-03-21)

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🤖 This CVE page is generated by defend.network from NVD, CISA KEV, EPSS, and our verified daily briefings. Severity and exploitation data come from official sources; always verify remediation steps against the official vendor advisory before acting in production.