Actively exploited · Published Mar 20, 2026 · Assigned by GitHub_M
CVE-2026-33017Langflow has Unauthenticated Remote Code Execution via Public Flow Build Endpoint
Critical 9.3 Exploited
In plain English
A critical-severity code injection in langflow from langflow-ai. Attackers are actively exploiting it in the wild (listed by CISA on March 25, 2026). The chance it is exploited in the next 30 days is estimated at 96.4% (higher than 99.9% of all known vulnerabilities). Ready-made attack tooling exists: Metasploit, Nuclei, public proof-of-concept code. Fixed versions are available - upgrade the affected package.
CISA guidance
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Federal agencies must remediate by Apr 8, 2026.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | langflow | 1.9.0 | GHSA-vwmf-pq79-vjvx |
| PyPI | langflow | 1.9.0 | PYSEC-2026-379 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| langflow-ai | langflow | < 1.9.0 |
Weakness: CWE-94, CWE-95, CWE-306 · Vector: 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
References
- https://github.com/langflow-ai/langflow/security/advisories/GHSA-vwmf-pq79-vjvx x_refsource_CONFIRM
- https://github.com/langflow-ai/langflow/commit/73b6612e3ef25fdae0a752d75b0fabd47328d4f0 x_refsource_MISC
- https://github.com/advisories/GHSA-rvqx-wpfh-mfx7 x_refsource_MISC
- https://www.sysdig.com/blog/cve-2026-33017-how-attackers-compromised-langflow-ai-pipelines-in-20-hours third-party-advisory
- https://medium.com/@aviral23/cve-2026-33017-how-i-found-an-unauthenticated-rce-in-langflow-by-reading-the-code-they-already-dc96cdce5896 exploit
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-33017 government-resource
- https://github.com/langflow-ai/langflow/releases/tag/1.8.2 patch