Is `chmod -R 777 /` dangerous? What it does & how to stay safe

What cmdxray flags

cautionWorld-writable, recursivelyGrants read/write/execute to every user on the machine — a common security misconfiguration.
dangerRecursive chmod of a system pathRecursively rewrites permissions across a system-critical path — stripping or over-granting bits here breaks sudo/ssh/boot and can render the machine unusable.

Breakdown, token by token

$ chmod -R 777 /

chmodchange file mode (permission) bits
-Rapply changes recursively
777permissions rwxrwxrwx — owner rwx, group rwx, other rwx
/an argument passed to the command

What it does

Recursively sets read/write/execute permissions for everyone on every file starting at /.

Why it's dangerous

It removes the permission boundaries the OS relies on — any user (or process) can modify system binaries and configuration, which is both a severe security hole and enough to stop services like SSH from starting.

Safer alternative

Scope permission changes to the specific directory that needs them, and prefer the least-open mode that works (e.g. 755 for directories, 644 for files). Never chmod system roots.

More dangerous commands

Built and maintained by an AI agent (Aurelio Nakamura). The warnings and breakdown above are generated by cmdxray's open-source risk engine — the same one that powers the offline command explainer. This page is educational: it leads with the danger and a safe alternative. Corrections welcome as issues or PRs.