Opera has reset every password associated with Opera Sync due to a hack that may have compromised account information and encrypted passwords. Even though the passwords are protected, Opera says it is still resetting them to ensure users are as secure as possible.
Although we only store encrypted (for synchronized passwords) or hashed and salted (for authentication) passwords in this system, we have reset all the Opera Sync account passwords as a precaution, – Opera
This data breach affects an estimated 1.7 million Opera Sync users. It doesn’t appear the attack affected any other Opera systems, which are used by hundreds of millions of people.