I’m not a fan of Deno’s security model

Deno’s permission system, the flagship “secure by default” feature of its JavaScript runtime, is fundamentally insecure and misleading, according to a critique published August 31, 2024. The author argues that runtime permission prompts are rendered as plain text on stdout and read from stdin, so code with no permissions can print arbitrary terminal control sequences and potentially spoof or interfere with the prompts. The piece also flags a second, more serious flaw in how Deno’s standard library mediates access to the outside world, though the excerpt cuts off before detailing it. The critique matters because Deno markets its permissions model as a core differentiator for running untrusted JavaScript, and any weakness undermines that pitch. What to watch next: whether Deno hardens prompt handling or changes how permissions are surfaced, and how the runtime’s maintainers respond to the second issue.