What happened
In December 2022 Telstra inadvertently published the names, addresses and phone numbers of about 132,000 customers who had paid to keep their numbers unlisted, through a database misalignment rather than a cyber attack [tel-acs]. The communications regulator, the ACMA, later confirmed formal regulator action over the disclosure of thousands of unlisted numbers [tel-acma].
Current status
Resolved with regulator action. This was an internal error, not a hack; the ~132,000 figure is as reported, and the ACMA has confirmed the unlisted-number disclosure [tel-acs], [tel-acma].
Why it matters
People pay for silent numbers precisely to stay unfindable — often for safety reasons — so publishing them is a real, targeted harm even without an attacker involved.