A significant data breach has occurred at Japanese telecommunications company KDDI, exposing approximately 14.2 million managed email credentials. The unauthorized access, detected on June 17th, was made possible by the exploitation of a vulnerability in third-party software used by the email service. KDDI's investigation revealed that the attackers took advantage of this security flaw to gain access to the system, which is used by the company and other local internet service providers. The fact that the vulnerability was exploited before a patch was available means that defenders were at a disadvantage1. This incident highlights the importance of proactive security measures, as relying solely on patches may not be sufficient to prevent such breaches. The exposure of millions of email credentials poses a significant risk to users, making it essential for them to take immediate action to secure their accounts, so what matters most to practitioners is the need to prioritize vulnerability management and implement robust security protocols to mitigate similar risks.