CVE-2026-33017

CVE-2026-33017 is a critical-severity vulnerability in Langflow with a CVSS 3.x base score of 9.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2026-03-25). The underlying weakness is classified as CWE-94.

Key facts

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.

Frequently asked questions

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.
How severe is CVE-2026-33017?
CVE-2026-33017 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-33017 being actively exploited?
Yes. CVE-2026-33017 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-03-25, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2026-33017?
CVE-2026-33017 affects Langflow. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-33017?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2026-33017 have an EU (EUVD) identifier?
Yes. CVE-2026-33017 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13556. It is also flagged as exploited in the EUVD (since 2026-03-25).
When was CVE-2026-33017 published?
CVE-2026-33017 was published on 2026-03-20 and last updated on 2026-06-17.

References

Affected products (1)

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