Of course we don't know who put Goldberg's email to have access.
That doesn't excuse though Goldberg's treasonous act of telling millions including the enemies.
This is a federal crime as Goldberg was NOT authorized to release any information he received even if it was accidental!
from this source:
18 U.S. Code § 798 - Disclosure of classified information
Whoever knowingly and willfully communicates, furnishes, transmits, or otherwise makes available to an
unauthorized person, or publishes, or uses in any manner prejudicial to the safety or interest of the United
States or for the benefit of any
foreign government to the detriment of the United
States any
classified information—
(1)concerning the nature, preparation, or use of any code, cipher, or
cryptographic system of the United
States or any
foreign government; or
(2)concerning the design, construction, use, maintenance, or repair of any device, apparatus, or appliance used or prepared or planned for use by the United
States or any
foreign government for cryptographic or
communication intelligence purposes; or
(3) concerning the
communication intelligence activities of the United
States or any
foreign government; or
(4)obtained by the processes of
communication intelligence from the communications of any
foreign government, knowing the same to have been obtained by such processes—
Shall be fined under this title or imprisoned not more than ten years, or both.
www.law.cornell.edu