Is CVE-2026-12940 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-12940 being exploited in the wild.

How severe is CVE-2026-12940?

Critical severity, with a CVSS score of 9.8, published 30 July 2026.

Which products and versions are affected?

IBM Langflow OSS 1.0.0 - 1.10.1.

Is there a fix for CVE-2026-12940?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-12940 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-12940?

Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-12940: IBM Langflow OSS remote code execution via environment variable injection

CVE-2026-12940 · Severity: critical · CVSS 9.8 · Published 2026-07-30

IBM Langflow OSS, a visual tool for building AI-powered agent workflows, contains a critical security flaw in its Model Context Protocol (MCP) component. An unauthenticated attacker can remotely execute arbitrary commands on the server hosting the application. This could lead to a complete system takeover, unauthorized access to sensitive AI models and data, or disruption of business operations.

Quick answers

Is CVE-2026-12940 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-12940 being exploited in the wild.
How severe is CVE-2026-12940?: Critical severity, with a CVSS score of 9.8, published 30 July 2026.
Which products and versions are affected?: IBM Langflow OSS 1.0.0 - 1.10.1.
Is there a fix for CVE-2026-12940?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-12940 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-12940?: Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

IBM Langflow OSS versions 1.0.0 through 1.10.1 are vulnerable to OS command injection (CWE-78) within the Model Context Protocol (MCP) stdio launcher. The vulnerability is located in 'src/lfx/src/lfx/base/mcp/util.py', where the 'DANGEROUS_ENV_VARS' blocklist fails to include sensitive environment variables such as SHELLOPTS, BASHOPTS, and PS4. An unauthenticated remote attacker can exploit this by injecting these variables during the MCP server configuration process to achieve arbitrary code execution with the privileges of the service process. IBM recommends upgrading to Langflow OSS version 1.10.2 to remediate this issue.

Affected products

IBM Langflow OSS 1.0.0 - 1.10.1

Timeline

2026-07-14: advisory: Initial publication of IBM security bulletin
2026-07-30: disclosed: NVD publication date

References

https://www.ibm.com/support/pages/node/7279995

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