The `quote()` function fails to validate object-token inputs against the operator model used by `parse()`. Specifically, the `.op` field is escaped using a regular expression that does not match line terminators such as `
`, `r`, `U+2028`, and `U+2029`. This allows line terminators to pass unescaped into the output. Since POSIX shells treat literal newlines as command separators, any content following the newline is executed as a separate command, leading to command injection. This issue is reachable through the direct construction of `{ op: '...
...' }` from external input or via `parse(cmd, envFn)` when `envFn` returns object tokens with an attacker-influenced `.op` field.