TeleMessage, an Israeli company that offers a modified version of Signal used by government agencies for message archiving, has been hacked. The hacker accessed customer data including the contents of direct messages and group chats from the modified versions of Signal, WhatsApp, Telegram, and WeChat. While no cabinet member's messages were obtained, the compromised data demonstrated vulnerabilities in the app's encryption process. Data related to Customs and Border Protection and Coinbase was also reportedly included in the breached material.
Modded Signal client used by trump admin has been hacked previously.
https://www.404media.co/the-signal-clone-the-trump-admin-uses-was-hacked/