Yonsei University portal breach exposes personal information of about 10,000 students and graduates

Yonsei University in Seoul announced on October 22, 2026 that unauthorized external access to its Yonsei Portal Service exposed personal information of about 10,000 current students and graduates. The exposed information includes student identification numbers, mobile phone numbers, email addresses, and certain system management data. Resident registration numbers were not compromised.

The university said it blocked the intrusion route, requested a police investigation, and apologised to those affected. Per person detail on exactly which information was exposed for each individual was posted on the university's website from 1 PM on Thursday, October 22.

Sources: Aju Press; Korea JoongAng Daily