n8n before 2.41.4 and 2.42.1 Send-and-Wait HMAC Signature Bypass via Waiting-Webhook

n8n before 2.41.4 and 2.42.x before 2.42.1 contains a signature bypass in the waiting-webhook endpoint, which selects Send-and-Wait validation before normalising an alternate node reference form. Attackers holding an execution's resume token can approve waiting executions meant for others, running downstream actions under the workflow owner's credentials, potentially including command execution.