[Anthropic Reports Leak of Account Information for Over 100 South Korean Companies Related to Claude] According to Yonhap News Agency, on November 9th, Anthropic, an American company, reported to the Korea Personal Data Protection Commission that the account information of over 100 South Korean companies using its generative AI service, Claude, had been leaked. The Commission stated on November 9th that Anthropic reported the incident on December 31st and it is currently in the preliminary review stage; a formal investigation has not yet been launched. According to a previous report by The Washington Post, the American security startup Cathedral exploited a vulnerability in third-party office software to access Anthropic's internal systems. Anthropic researcher Lydia Hallie stated on X that Cathedral accessed account information such as names, email addresses, and subscription plans without authorization, but did not obtain prompts, output results, or payment information. The company blocked the affected systems and fixed the vulnerability on the same day it became aware of the breach.