CVE-2026-12940: CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in IBM Langflow OSS
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.
AI Analysis
Technical Summary
CVE-2026-12940 is an OS command injection vulnerability in IBM Langflow OSS (versions 1.0.0 through 1.10.1) caused by incomplete environment variable filtering in the MCP stdio launcher component (src/lfx/src/lfx/base/mcp/util.py). The DANGEROUS_ENV_VARS blocklist omits critical environment variables (SHELLOPTS, BASHOPTS, PS4), enabling unauthenticated remote code execution via environment variable injection. This vulnerability has a CVSS 3.1 base score of 9.8, indicating critical severity with network attack vector, no privileges required, no user interaction, and high impact on confidentiality, integrity, and availability.
Potential Impact
Successful exploitation allows unauthenticated remote attackers to execute arbitrary code on the affected IBM Langflow OSS systems, potentially leading to full system compromise, data loss, and service disruption.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict network access to the affected service and monitor for suspicious activity related to environment variable manipulation.
CVE-2026-12940: CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in IBM Langflow OSS
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 v3.1
Score 9.8critical
Affected software
pkg:github/ibm/langflow_osscpe:2.3:a:ibm:langflow_oss:1.0.0:*:*:*:*:*:*:*cpe:2.3:a:ibm:langflow_oss:1.10.1:*:*:*:*:*:*:*Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-12940 is an OS command injection vulnerability in IBM Langflow OSS (versions 1.0.0 through 1.10.1) caused by incomplete environment variable filtering in the MCP stdio launcher component (src/lfx/src/lfx/base/mcp/util.py). The DANGEROUS_ENV_VARS blocklist omits critical environment variables (SHELLOPTS, BASHOPTS, PS4), enabling unauthenticated remote code execution via environment variable injection. This vulnerability has a CVSS 3.1 base score of 9.8, indicating critical severity with network attack vector, no privileges required, no user interaction, and high impact on confidentiality, integrity, and availability.
Potential Impact
Successful exploitation allows unauthenticated remote attackers to execute arbitrary code on the affected IBM Langflow OSS systems, potentially leading to full system compromise, data loss, and service disruption.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict network access to the affected service and monitor for suspicious activity related to environment variable manipulation.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- ibm
- Date Reserved
- 2026-06-22T19:44:45.455Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a6b81679c2644c7f860e91e
Added to database: 07/30/2026, 16:52:55 UTC
Last enriched: 07/30/2026, 17:11:16 UTC
Last updated: 07/30/2026, 18:23:20 UTC
Views: 5
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