CVE-2026-33017 Langflow Code Injection
Unauthenticated attackers can execute arbitrary Python code via the public flow build endpoint in Langflow.
- Exploited in the wild
- Since 25 Mar 2026
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-33017?
CVE-2026-33017 is a critical code injection vulnerability in Langflow Langflow, published on 20 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-33017?
3 open source packages ship an affected version, including langflow. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
langflow PyPI | All versions | 1.9.0 |
langflow PyPI | All versions | 1.9.0 |
langflow PyPI | All versions | 1.9.0 |
Products include Langflow Langflow.
How do I fix CVE-2026-33017?
Upgrade langflow to 1.9.0 or later. US federal agencies must fix it by 8 Apr 2026.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-33017 being exploited?
Yes. Attackers have exploited CVE-2026-33017 in the wild since at least 25 Mar 2026.
Public exploit code: 1 Metasploit module, 1 Exploit-DB entry, 1 Nuclei template and 27 proofs of concept on GitHub.
Other vulnerabilities in Langflow Langflow
Sources
Also known as GHSA-vwmf-pq79-vjvx, PYSEC-2026-379.