Langflow Code Injection Vulnerability
langflow-ai — langflow
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.
9.3
98.2%
Vector breakdown
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- None
- User interaction
- None
- Confidentiality (Vulnerable System)
- High
- Integrity (Vulnerable System)
- High
- Availability (Vulnerable System)
- High
- Confidentiality (Subsequent System)
- Low
- Integrity (Subsequent System)
- Low
- Availability (Subsequent System)
- Low
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L
- Published
- Mar 20, 2026
- Modified
- May 21, 2026
- Added to KEV
- Mar 25, 2026
- Federal patch due
- Apr 8, 2026
CISA 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.
Weakness classification
Proof-of-concept & exploitation references
Weaponization
Public repositories whose name or description references CVE-2026-33017, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit - cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.
No public GitHub repositories referencing CVE-2026-33017 were found at last check. Absence here is not proof no exploit exists - see the references below for vendor advisories and write-ups.
References
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 base score of 9.3 out of 10 (CVSS 4.0).
Is CVE-2026-33017 actively exploited in the wild?
Yes. CVE-2026-33017 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Mar 25, 2026, meaning CISA has confirmed evidence of active exploitation.
What is the EPSS score for CVE-2026-33017?
98.2% - meaning FIRST.org's EPSS model estimates a 98.2% probability this vulnerability will be exploited in the wild within 30 days (100% percentile among all scored CVEs).
Is there exploit tooling available for CVE-2026-33017?
Yes - a public Nuclei template referencing CVE-2026-33017 exist in public repositories we checked.
What type of vulnerability is CVE-2026-33017?
CVE-2026-33017 is classified under CWE-94, CWE-95, CWE-306 (CWE-94: Improper Control of Generation of Code ('Code Injection')).
Cross-checked against
Impactr finds and proves whether CVE-2026-33017 - or flaws like it - are actually reachable in your own web apps and APIs, with a reproducible exploit as evidence.
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