Per this ARSTtechnica article from Oct 5, 2021, Syniverse hasn’t revealed whether text messages were exposed.

Syniverse hacked for 5 years

Syniverse, a company that routes hundreds of billions of text messages every year for hundreds of carriers including Verizon, T-Mobile, and AT&T, revealed to government regulators that a hacker gained unauthorized access to its databases for five years. Syniverse and carriers have not said whether the hacker had access to customers’ text messages.

The article reveals there was a breach discovered by Syniverse and remained undiscovered for 5 months from May 2021. Syniverse did not uncover whether there was data exfiltrated (taken from them and copied).

Syniverse did not observe any evidence of intent to disrupt its operations or those of its customers and there was no attempt to monetize the unauthorized activity… While Syniverse believes it has identified and adequately remediated the vulnerabilities that led to the incidents described above, there can be no guarantee that Syniverse will not uncover evidence of exfiltration or misuse of its data or IT systems from the May 2021 Incident, or that it will not experience a future cyber-attack leading to such consequences. Any such exfiltration could lead to the public disclosure or misappropriation of customer data, Syniverse’s trade secrets or other intellectual property, personal information of its employees, sensitive information of its customers, suppliers and vendors, or material financial and other information related to its business.

We certainly need more accountability from these large companies we place our trust in their technology. Their statement is extremely vague and leaves the question whether they are capable to handling our private information.