IBM Langflow OSS versions 1.0.0 through 1.10.1 are affected by a critical unauthenticated remote code execution vulnerability. The flaw resides in the MCP (Model Context Protocol) stdio launcher, specifically in src/lfx/src/lfx/base/mcp/util.py. The vulnerability arises because the DANGEROUS_ENV_VARS blocklist fails to include the SHELLOPTS, BASHOPTS, and PS4 environment variables. An unauthenticated attacker can inject these environment variables to achieve arbitrary code execution on the target system. No authentication is required to exploit this vulnerability, making it especially severe. IBM has published an advisory on their support pages addressing the issue. Users are urged to upgrade or apply mitigations immediately.