Forward from: BLM Philly 2020
The SMS verification provider for Signal got hacked. Signal itself did not get hacked. Essentially, it's possible for some people (not many) to have their Signal account hijacked by someone registering their own Signal app for that phone number. You can prevent this by enabling "registration lock" for your profile by going to Settings > Account > Registration Lock, which requires your PIN to register Signal on a new phone.
https://nitter.net/signalapp/status/1559221383107854336#m
https://signal.org/smshelp
https://nitter.net/signalapp/status/1559221383107854336#m
https://signal.org/smshelp