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Sweep 22 Oct 2026 · 04:32Z Build v2.1.308 527 read Stable v2.1.308 Latest v2.1.308 Next v2.1.308 Feeds RSS JSON llms.txt llms-full.txt Unofficial
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Claude Code v2.1.305 ·

Nested user namespace sandbox setting now covers WSL and more tools

sandbox.allowNestedUserNamespaces now also applies on WSL, names more tools that need it, and stays off by default

Use it now Improvements
JSON All of v2.1.305
Use it nowTier: how much it should matter to you
2Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
SandboxArea: what it touches
ImprovementsKind: in v2.1.305,
What probably matters to youSection of the release
What

The sandbox.allowNestedUserNamespaces setting lets commands inside the sandbox create their own user namespaces, a Linux feature some programs use to fence themselves off. Its description now:

  • covers WSL (Windows Subsystem for Linux) as well as Linux
  • lists Chromium and Electron apps, rootless podman and buildah, a nested bubblewrap, and unshare as tools that need it
  • warns that turning it on removes the sandbox's isolation of the code it runs

It remains off by default. When Claude Code runs commands through /bin/sh in the sandbox, it now explicitly turns nested user namespaces off.

Why

The setting is a way to let rootless containers and Chromium-based tools run inside the sandbox, at a stated security cost. Turn it on only when such a tool fails without it.

Read from
Names in the bundlesandbox.allowNestedUserNamespaces
Since it was published

The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.

Confirmed since Anthropic's documentation has since written up sandbox.allowNestedUserNamespaces, on Configure the sandboxed Bash tool. * To keep Chromium's or Electron's own sandbox, or to run a nested bubblewrap or `unshare`, set [`sandbox.allowNestedUserNamespaces`](/docs/en/settings-reference#sandbox-allownestedusernamespaces) to `true` in `~/.claude/settings.json`, no… sandboxing see the edit
How sure we are
Two sources agreeTwo things we can check say the same as this entry.
Anthropic's documentation agreesAnthropic's documentation has since written up sandbox.allowNestedUserNamespaces, on Configure the sandboxed Bash tool.
Anthropic's release notes agreeAdded sandbox.allowNestedUserNamespaces so sandboxed commands on Linux can create user namespaces (Chromium, rootless podman); this lets…

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