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RuleRoster

Source-backed platform rule

Deno sensitive system I/O permissions

Deno's sandbox denies most sensitive system I/O by default while documenting limited default operations, explicit permission categories, deny precedence, and the allow-all sandbox opt-out.

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Direct answer

What is the rule?

Deno runs code in a secure sandbox. By default, most sensitive system I/O is denied and explicit read, write, network, environment, subprocess, system, FFI, or import permission is required; explicit deny flags take precedence over allow flags. Some I/O remains available in limited capacity by default, so this is not a claim that all I/O is denied. `--allow-all` disables the sandbox rather than preserving least privilege.

Scope
Deno runtime, module, dependency-integrity, and pack rules
Human verified
August 14, 2026
Source checked
September 3, 2026

Published evidence

Rule details

Sensitive system I/O permissions

Deno's secure sandbox denies most sensitive system I/O by default. Read, write, network, environment, subprocess, system, FFI, and import access require explicit permission; deny flags take precedence. Some I/O remains available in limited capacity by default, so this is not an all-I/O denial. `--allow-all` disables the sandbox.

Applicability

Service: Deno. Rule group: runtime-sandbox. Scope is limited to this exact topic and its source-stated qualifiers.

Evidence trail

Official sources

Attribution and license

Deno documentation by the Deno authors, Copyright (c) 2018-2024 the Deno authors. Source: https://github.com/denoland/docs/tree/aa772cfbe4455e2a3ef86e9f4df584d41523c0f9. Licensed under the MIT License: https://github.com/denoland/docs/blob/aa772cfbe4455e2a3ef86e9f4df584d41523c0f9/LICENSE. Modified by RuleRoster: RuleRoster extracted and restructured facts into typed rule fields and concise answers. Verified 2026-08-14. No endorsement by Deno or the Deno authors is implied. Project names and marks remain descriptive source identifiers only.

Interpretation and accountability

Before you act

  1. Confirm that the scope matches your case.
  2. Keep recommendations, enforced limits, exceptions, and unstated details distinct.
  3. Open the official source before relying on the rule for a consequential decision.

Record dates

Published
August 15, 2026
Human verified
August 14, 2026
Source checked
September 3, 2026
Review due
September 4, 2026

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