How long the Dubai CID can held the accused under...

According to the UAE Criminal Procedures Law, the detention order issued by the Public Prosecution comes after interrogating the accused for a period of SEVEN days, which could be renewed for another period not exceeding fourteen days.
If the interest of the investigation requires continuation of the precautionary detention of the accused after the expiration of the periods referred to in the aforementioned paragraph, the Public Prosecution must present the documents to a judge at a competent criminal court to issue order after reviewing the papers and hearing the accused’s statements to extend the detention for a period not exceeding thirty days, subject to renewal or release provided with or without a warranty.
The accused can file a grievance / appeal to the Head of the Court against the order issued in his / her absence to extend the detention within three days from the date of notification of the matter and get aware of it.