Nippon Steel Solutions experienced a significant data breach involving a zero-day cyber attack that exploited a previously unknown software vulnerability in their network infrastructure. The breach, detected on March 7, 2025, compromised customer, partner, and employee personal information. The attack specifically targeted network equipment vulnerabilities before patches were available, making it particularly challenging to defend against. The compromised data includes names, organizational affiliations, job titles, company addresses, business email addresses, phone numbers, and employee department information. Despite the breach, the company’s cloud services remain unaffected. Nippon Steel has taken comprehensive measures to address the breach and prevent future incidents, including consulting with law enforcement, notifying affected parties, and implementing enhanced security measures.