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Vulnerability record · CVE-2026-12940 · published 30 July 2026

CVE-2026-12940: Langflow os command injection vulnerability

Langflow · Langflow

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.

9.8 CVSS 3.1 Critical EPSS 0.94% · top 40.5% CWE-78 · OS command injection
9.8CVSS 3.1 base score
0.94%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
1References
4 Aug 2026Last modified by NVD

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.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://www.ibm.com/support/pages/node/7279995 Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2026-9198Langflow auto_login and code validation chain enables unauthenticated RCEIBM Langflow OSS 1.0.0 through 1.10.0 exposes /api/v1/auto_login, which mints SUPERUSER tokens to any network caller, and /api/v1/validate/code, whic…KEVEPSS 29%analysed9.8CVE-2026-0770Langflow validate endpoint exec_globals remote code executionLangflow mishandles the exec_globals parameter passed to its validate endpoint, allowing functionality from an untrusted control sphere to be include…KEVEPSS 64%analysed9.8CVE-2025-3248Langflow unauthenticated code injection in validate/code endpointLangflow versions prior to 1.3.0 expose the /api/v1/validate/code endpoint without authentication, allowing code injection. A remote attacker can sen…KEVEPSS 100%analysed9.4CVE-2025-34291Langflow CORS misconfiguration leads to token theft and RCELangflow up to and including 1.6.9 ships an overly permissive CORS configuration (allow_origins='*' with allow_credentials=True) and a refresh token …KEVEPSS 93%analysed9.3CVE-2026-33017Langflow build_public_tmp endpoint unauthenticated remote code executionLangflow versions prior to 1.9.0 expose the POST /api/v1/build_public_tmp/{flow_id}/flow endpoint without authentication, and when the optional data …KEVEPSS 25%analysed8.4CVE-2026-55255Langflow IDOR in responses endpoint allows cross-user flow executionLangflow before 1.9.1 has an insecure direct object reference in the /api/v1/responses endpoint. An authenticated attacker can supply another user's …KEVEPSS 0.89%analysed10.0CVE-2026-10134Langflow code injection vulnerabilityIBM Langflow OSS 1.0.0 through 1.9.3 allows an attacker to read every secret available to the Langflow process, read and modify every flow, conversat…EPSS 0.64%10.0CVE-2026-10561Langflow code injection vulnerabilityIBM Langflow OSS 1.0.0 through 1.9.3 has an vulnerability due to an improper isolation of Python execution combined with an authentication bypass tha…EPSS 1.0%

Source: NIST National Vulnerability Database (record CVE-2026-12940), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.