Carnival Corporation has been compromised by a ransomware attack that occurred on August 15, which the company says “accessed and encrypted a portion of one brand’s information technology systems.”

“Based on its preliminary assessment and on the information currently known (in particular, that the incident occurred in a portion of a brand’s information technology systems), the Company does not believe the incident will have a material impact on its business, operations or financial results,” the company wrote in an SEC filing. “Nonetheless, we expect that the security event included unauthorized access to personal data of guests and employees, which may result in potential claims from guests, employees, shareholders, or regulatory agencies.”

The company added that while its internal investigation has found no other brand’s IT systems within the company have been compromised by the attack so far, “there can be no assurance that other information technology systems of the other Company’s brands will not be adversely affected.”

Carnival noted that it is “working with industry-leading cybersecurity firms to immediately respond to the threat, defend the company’s information technology systems, and conduct remediation.”

A spokesperson for Carnival Corporation did not immediately return 360aproko news’ request for comment on exactly how many people may have been impacted by the attack.