CVE-2026-12940 Command injection in Langflow OSS

What is CVE-2026-12940?

CVE-2026-12940 is a critical command injection vulnerability in Langflow Langflow, published on 30 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

IBM Langflow OSS 1.0.0 through 1.10.1  are vulnerable to unauthenticated remote code execution via environment variable injection in the MCP (Model Context Protocol) stdio launcher. The vulnerability exists in src/lfx/src/lfx/base/mcp/util.py where the DANGEROUS_ENV_VARS blocklist fails to include SHELLOPTS , BASHOPTS , and PS4 environment variables.

Weakness: CWE-78

Which versions are affected by CVE-2026-12940?

It affects 1 product.

Products include Langflow Langflow.

How do I fix CVE-2026-12940?

No fix has been published for CVE-2026-12940 yet. Limit exposure of the affected software until one is available.

Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.

Is CVE-2026-12940 being exploited?

There is no known exploitation of CVE-2026-12940 in the wild and no public exploit code.

Public exploit code: 1 proofs of concept on GitHub.

Other vulnerabilities in Langflow Langflow

• CVE-2026-9198 IBM Langflow Code Injection Exploited Critical 9.8
• CVE-2026-0770 Langflow Inclusion of Functionality from Untrusted Control Sphere Exploited Critical 9.8
• CVE-2025-3248 Langflow Missing Authentication Exploited Critical 9.8
• CVE-2025-34291 Langflow Origin Validation Error Exploited Critical 9.4
• CVE-2026-33017 Langflow Code Injection Exploited Critical 9.3

All Langflow Langflow vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-gx45-8jc3-gqqr.