{"name":"sandbox.allowNestedUserNamespaces","slug":"sandbox-allownestedusernamespaces","family":"setting","title":"Settings keys","noun":"settings key","description":"Let [sandboxed](\/docs\/en\/sandboxing#chromium-or-rootless-podman-fails-inside-the-sandbox-on-linux) commands create user namespaces on Linux and WSL2","description_source":"docs","described_by":{"doc":"claude-code\/settings-reference","title":"All settings"},"presence":{"first_seen":null,"removed_in":null,"in_current_build":false,"newest_mined":"2.1.308","builds":0,"mined_builds":149,"first_cited":{"version":"2.1.305","released_at":"2026-10-20 19:29:36","spans":2}},"aliases":[],"entries":[{"version":"2.1.305","anchor":"device-tool-refusal-text-adds-sandboxallownestedusernamespa","heading":"Device-tool refusal now names the nested user namespaces sandbox setting","line":"The message about device tools being withheld now lists `sandbox.allowNestedUserNamespaces` among the settings that weaken isolation","released_at":"2026-10-20 19:29:36","reason":"found in this entry's text, named in this entry"},{"version":"2.1.305","anchor":"new-sandbox-setting-allownestedusernamespaces","heading":"Nested user namespace sandbox setting now covers WSL and more tools","line":"`sandbox.allowNestedUserNamespaces` now also applies on WSL, names more tools that need it, and stays off by default","released_at":"2026-10-20 19:29:36","reason":"found in this entry's text, named in this entry"},{"version":"2.1.305","anchor":"sandbox-refuses-a-setting-that-lets-commands-bypass-file-den","heading":"Turning on nested user namespaces in the sandbox is now a reason to refuse","line":"Claude Code now refuses an action when `sandbox.allowNestedUserNamespaces` is on, because it lets commands get around file deny rules","released_at":"2026-10-20 19:29:36","reason":"found in this entry's text, named in this entry"},{"version":"2.1.304","anchor":"new-sandbox-setting-allownestedusernamespaces","heading":"New sandbox setting lets sandboxed commands create their own user namespaces","line":"A new `allowNestedUserNamespaces` sandbox setting, off by default and Linux only, lets browsers or rootless podman work inside the sandbox at a security cost","released_at":"2026-10-19 19:47:15","reason":"named in this entry, found in this entry's text"}],"entries_total":4,"docs":[{"source":"claude-code","path":"settings-reference","title":"All settings","documented":true},{"source":"claude-code","path":"changelog","title":"Claude Code changelog","documented":false},{"source":"claude-code","path":"sandboxing","title":"Configure the sandboxed Bash tool","documented":false},{"source":"claude-code","path":"server-managed-settings","title":"Configure server-managed settings","documented":false}],"docs_total":4,"gates":[],"related":[{"name":"sandbox","slug":"sandbox","description":"[Isolate Bash commands](\/docs\/en\/sandboxing) from your filesystem and network on macOS, Linux, and WSL2"},{"name":"sandbox.bwrapPath","slug":"sandbox-bwrappath","description":"Point the [sandbox](\/docs\/en\/sandboxing) at a bubblewrap binary outside `PATH`"},{"name":"sandbox.credentials","slug":"sandbox-credentials","description":"Hide or mask credential files and variables inside the [sandbox](\/docs\/en\/sandboxing#protect-credentials)"},{"name":"sandbox.credentials.awsPairs","slug":"sandbox-credentials-awspairs","description":"Link custom-named AWS key variables into one credential for [re-signing](\/docs\/en\/sandboxing#re-sign-aws-requests)"},{"name":"sandbox.credentials.files","slug":"sandbox-credentials-files","description":"Block or mask reads of a credential file inside the [sandbox](\/docs\/en\/sandboxing#mask-credential-files)"},{"name":"sandbox.enabled","slug":"sandbox-enabled","description":"Turn on [Bash sandboxing](\/docs\/en\/sandboxing#get-started) on macOS, Linux, and WSL2"},{"name":"sandbox.excludedCommands","slug":"sandbox-excludedcommands","description":"Name commands Claude Code can run outside the [sandbox](\/docs\/en\/sandboxing)"},{"name":"sandbox.failIfUnavailable","slug":"sandbox-failifunavailable","description":"Refuse to start when the [sandbox](\/docs\/en\/sandboxing) can't, instead of running unsandboxed"},{"name":"sandbox.filesystem","slug":"sandbox-filesystem","description":"Control which paths [sandboxed](\/docs\/en\/sandboxing#filesystem-isolation) commands can read and write"},{"name":"sandbox.filesystem.allowRead","slug":"sandbox-filesystem-allowread","description":"Re-open reading inside a region [`denyRead`](#sandbox-filesystem-denyread) blocks"}],"url":"https:\/\/changelogs.core-directive.com\/reference\/setting\/sandbox-allownestedusernamespaces","family_url":"https:\/\/changelogs.core-directive.com\/reference\/setting.json"}