CVE-2026-62863

MoLing is a computer-use and browser-use based MCP server. Prior to 0.5.0, when MoLing runs in SSE mode using -l, its /sse and /message HTTP endpoints do not authenticate requests and the mcp-go dependency sets Access-Control-Allow-Origin: *. A malicious web page can open a cross-origin EventSource to /sse, including a loopback listener, and read the endpoint event to obtain sessionId. After a victim running SSE mode visits that page, the attacker can use the disclosed sessionId against /message to send unauthorized MCP tool calls. Depending on the configured tools, those calls can read or write local files, execute commands or perform other actions. Binding only to loopback does not prevent this browser-mediated attack. This issue is fixed in version 0.5.0.