Week 1, 2026 security incident report
Hacking and data breach incidents newly reported 2025.12.29 ~ 01.04
Between 29 December 2025 and 4 January 2026, four new cyber-security incidents occurred in South Korea, with the leak of 900,000 personal records at a certified medical institution standing out in terms of stated scale. The leak of personal data of Weverse fan-signing event winners was covered in seven articles, the most of any South Korean incident, and Inha University suffered both a personal data leak and a 14-hour website outage owing to a ransomware attack. Hacking damage at all three of South Korea's mobile operators was also confirmed, with data leaks and breaches occurring across multiple sectors, including healthcare, education, telecoms and fan platforms. Overseas, 23 new incidents occurred, with key cases including the leak of patients' medical records at New Zealand's Manage My Health, the leak of data on 2.4 million WIRED accounts and a ransomware attack on Sedgwick's government contracting subsidiary.
By type
- Hacking & intrusion9
- Data breach9
- Ransomware7
- Malware1
- DDoS1
Key incidents in South Korea
Personal data of Weverse fan-signing event winners leaked
Impact: Personal data of fan-signing event winners
The leak of personal data of fan-signing event winners at Weverse came to light on 2 January 2026. Weverse immediately removed the staff member involved in the misconduct from their duties. Allegations of rigging in the selection of fan-signing event winners were later raised.
Related reports: 7 · last report →Ransomware attack on Inha University disables website and leaks personal data
Impact: Personal data leak and 14-hour website outage
Inha University was hit by a ransomware attack that took its website offline; it was restored after 14 hours. The university subsequently confirmed a personal data leak and took legal action against Gunra. Members announced plans for a group damages claim, and the university issued an official apology and launched a full review of its security systems.
Related reports: 4 · last report →900,000 personal records leaked even at certified medical institution
900kImpact: 900,000 personal records
900,000 personal records were leaked from a certified medical institution. The action taken over the leak was limited to an administrative fine and a recommendation for improvement.
Read on JTBC ↗All three South Korean mobile operators hit by hacking
Impact: Hacking damage at South Korea's three mobile operators
All three of South Korea's mobile operators have suffered hacking incidents. The extent of the damage at each company, when the breaches took place and the responses have not been confirmed.
Read on 한국경제 ↗
Key incidents in other countries
Hack of New Zealand's Manage My Health steals medical documents of about 100,000 people
100kImpact: Theft of medical documents of about 100,000 people
New Zealand patient portal Manage My Health was hacked, and medical documents of about 100,000 people were stolen, with personal health records appearing on the dark web. Notification of affected patients began, but about 47,000 people had no contact details, delaying their notification. The final investigation also identified a personal data handling problem in which hospital records of patients without accounts had been brought into the portal.
Related reports: 11 · last report →Link raised between cyber-attack and blackout during operation to capture Venezuela's Maduro
Impact: Blackout in Caracas, Venezuela
The possibility was raised that a US cyber-attack was involved in the blackout that occurred in Venezuela during the operation to capture Maduro. Trump suggested that the US had cut off power with a cyber-attack during the strike, and further information supporting the role of a cyber-attack emerged afterwards.
Related reports: 6 · last report →Sedgwick government contracting subsidiary hit by ransomware attack and data leak
A cyber intrusion and data leak took place at Sedgwick's government contracting subsidiary. Sedgwick confirmed the incident, and the TridentLocker ransomware group claimed the attack.
Related reports: 5 · last report →Cyber-attack on Apple's Chinese assembly partner raises data exposure concerns
Apple's assembly partner in China was hit by a supply chain cyber-attack. When the attack came to light in December 2025, the possibility was raised that manufacturing data and Apple's confidential information had been exposed. Whether data was actually leaked and the extent of the damage have not been confirmed.
Related reports: 4 · last report →WIRED hack exposes 2.4 million accounts
2.4mImpact: Information on 2.4 million accounts
Tech publication WIRED was hacked, exposing subscriber and account information. In December 2025, the personal data of 2.3 million subscribers was reported to have been leaked on the dark web. In January 2026, the number of affected accounts was put at 2.4 million.
Related reports: 3 · last report →