OpenClaw: MCP stdio server env could load dangerous startup variables from workspace config

## Affected Packages / Versions - Package: `openclaw` (npm) - Affected versions: `< 2026.4.20` - Patched version: `2026.4.20` ## Impact Workspace MCP stdio configuration could pass dangerous process-startup environment variables such as `NODE_OPTIONS`, `LD_PRELOAD`, or `BASH_ENV` to the spawned MCP server process. In a malicious workspace, this could make the MCP child load attacker-controlled code when the operator starts a session that uses that MCP server. The impact is limited to local/workspace trust boundaries and requires the operator to run OpenClaw in a workspace containing the malicious MCP configuration. Severity is therefore medium, not high/critical. ## Fix OpenClaw now filters MCP stdio environment entries through the host environment safety denylist before spawning stdio MCP servers. Fix commits: - `62fa5071896e95edc7f67d1cebc70a2859e283af` - `85d86ebc4bf3d2226d39d132a484f4f7a299fa1b` ## Release Fixed in OpenClaw `2026.4.20`.