CVE-2026-12940

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

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

EPSS

0.68% chance of exploitation in the next 30 days, 50th percentile

Published

2026-07-30

Updated

2026-07-31

Proof-of-concept exploits (1)

• BiiTts/CVE-2026-12940-Langflow-Unauth-RCE

References

• CVE Record
• NVD entry

Related

• CVE-2025-1974
• CVE-2025-49113
• CVE-2026-44789
• CVE-2026-46490
• CVE-2026-49230
• CVE-2026-49468