What is the CVSS score of CVE-2026-27966?

CVE-2026-27966 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.4%.

Which versions of Python are affected by CVE-2026-27966?

Langflow versions prior to 1.8.0 contain a critical vulnerability that allows unauthenticated attackers to execute arbitrary Python code on affected systems.. A patch is available.

Is there a public PoC exploit available for CVE-2026-27966?

Yes, a public proof-of-concept exploit is available for CVE-2026-27966. Prioritise patching immediately. EPSS: 0.4%.

How to fix or mitigate CVE-2026-27966?

Within 24 hours: Identify all systems running Langflow versions prior to 1.8.0 and assess exposure (internet-facing, internal access, data sensitivity). Within 7 days: Apply vendor patch to upgrade all affected instances to version 1.8.0 or later, or implement network-level compensating controls if patching is delayed. Within 30 days: Conduct forensic review of logs for exploitation attempts, validate patch deployment across all systems, and perform security testing to confirm remediation.

Python CVE-2026-27966

CRITICAL

Code Injection (CWE-94)

2026-02-26 security-advisories@github.com

GHSA-3645-fxcv-hqr4

Python RCE Command Injection AI / ML Langflow Langchain

9.8

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

9.8 CRITICAL

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

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:55 vuln.today

PoC Detected

Feb 28, 2026 - 00:54 vuln.today

Public exploit code

Patch released

Feb 28, 2026 - 00:54 nvd

Patch available

CVE Published

Feb 26, 2026 - 02:16 nvd

CRITICAL 9.8

DescriptionGitHub Advisory

Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to version 1.8.0, the CSV Agent node in Langflow hardcodes allow_dangerous_code=True, which automatically exposes LangChain’s Python REPL tool (python_repl_ast). As a result, an attacker can execute arbitrary Python and OS commands on the server via prompt injection, leading to full Remote Code Execution (RCE). Version 1.8.0 fixes the issue.

Articles & Coverage 1

POC CVE-2026-27966 Langflow RCE Exploit Tool with Interactive Shell Mar 06, 2026

AnalysisAI

Code injection in Langflow CSV Agent node before 1.8.0. The node hardcodes allow_dangerous_code=True, enabling arbitrary code execution through crafted CSV files. EPSS 0.41% with PoC and patch available.