Langflow: IBM Langflow OSS 1.0.0 through 1.10.1 are vulnerable to unauthenticated remote code execution…
Langflow
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- Severity
- Critical, CVSS 9.8
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Record
- CVE-2026-12940
- Affects
- Langflow
- Known exploited
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Published
- Record first published by the source
- July 30, 2026
- Source last modified
- October 23, 2026
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.
Description quoted from the NVD record.
Who is affected
Langflow (also called IBM Langflow OSS) is a tool for building apps that use AI language models. This flaw affects versions 1.0.0 through 1.10.1. The problem is in the part of the product that starts connected helper tools using the Model Context Protocol, a standard way for AI apps to link to outside tools. That part fails to block certain system settings an outsider can slip in. Because of this, an attacker who has not logged in could run their own commands on the computer running Langflow. This flaw is rated Critical.
What to do
- If someone in your organization installed or runs Langflow, ask them to check which version is in use. Versions 1.0.0 through 1.10.1 are affected.
- No fixed version is named for this flaw yet, so check the vendor advisory linked on this page for a fixed release, and have that person install it as soon as one is available.
- If an IT provider or vendor runs Langflow for your organization, send them this advisory and ask when the update will be done.
Analysis written from the source record as of October 23, 2026 and reviewed before publishing.