The npm package @yongot/canary-mcp-isolation contains malicious code that exfiltrates host identifiers and cloud metadata information to a third-party webhook without user consent. This data exfiltration occurs automatically during package installation and import, sending information such as the installer's hostname, a persisted run marker, and cloud instance metadata reachability. The package claims to be a benign canary for authorized testing, but this does not mitigate the unauthorized data transmission.