JCOM Co., Ltd. Affected by KDDI Corporation Data Breach
Data breach exposes up to 14.2 million email logins at six ISPs Japanese telecommunications operator KDDI Corporation disclosed a data breach where threat actors gained access to one of its email systems used by five…
Key points
- JCOM Co., Ltd. was impacted by a data breach originating from KDDI Corporation's email system.
- Unauthorized access to the shared email system by exploiting a third-party software vulnerability.
- Potential exposure of email addresses and passwords for JCOM customers.
Connected intelligence
Signal brief
Follow the organization, likely method and potential impact to explore connected Shadow Tier intelligence.
Organization
- Published
- Jun 28, 2026
- Updated
- Jul 22, 2026
- Confidence
- Medium
- Evidence
- 5 sources
Structured assessment
Signal analysis
This analysis groups the signal by industry, likely incident action and impacted security area. It helps compare this signal with other published signals without treating the labels as final determinations.
Threat source
Watch internet-facing systems, credential abuse and exploit activity.
Business impact
- Impact area
- Confidentiality
- Likely asset
- User or customer data
Mentioned entities
Quick context
Questions about this signal
What happened in this signal?
Data breach exposes up to 14.2 million email logins at six ISPs Japanese telecommunications operator KDDI Corporation disclosed a data breach where threat actors gained access to one of its email systems used by five other internet service providers (ISPs) in the country. The company says that it discovered the compromise on June 17 and responded immediately by blocking the attacker and implementing defense measures. The investigation determined that the hackers exploited a vulnerability in an unnamed third-party software that KDDI Corporation used on its system. “Although technical defensive measures have already been implemented for the system, there remains a possibility that customers' email addresses and passwords were obtained by unauthorized third parties as a result of the incident,” KDDI warns . KDDI is one of Japan’s largest ISPs, with 45,000 employees and an annual revenue of $32.4 billion. It is a public entity that has operated since 2000, following the merger of IDO, DDI, and KDD, Japan's former state-monopoly international telecommunications provider. The company says that the incident impacted the following five ISP operators and their email services: Although the investigation into the incident is still underway and the exact number of impacted accounts has yet to be determined, KDDI said it may have exposed the email addresses and passwords of up to 14,22 million customers. This figure includes current and former customers, as well as inactive accounts that may no longer be in use. Another mitigating factor, according to KDDI, is that some passwords were stored in hashed and/or encrypted form, meaning that they cannot be readily abused for account hijacks even if exposed. However, KDDI did not specify what type of encryption was used or what percentage of accounts had passwords stored in plaintext. KDDI says it has been contacting affected ISPs since June 17 and has also notified Japan's Personal Information Protection Commission and the Ministry of Internal Affairs and Communications. The company is currently working with affected ISPs to implement additional security measures to mitigate the risks arising from this exposure. Meanwhile, customers who may have been exposed are advised to reset their email account passwords as soon as possible. If two-factor authentication (2FA) is available, it would be prudent to set it up as well for additional protection. Security teams log 54% of successful attacks and alert on just 14%. The rest move through your environment unseen. The Picus whitepaper shows how breach and attack simulation tests your SIEM and EDR rules so threats stop slipping by detection. Telco giant KDDI says data breach affects over 12 million people Insurance giant Aflac discloses data breach after subsidiary hack Japanese energy firm loses drive with data of 10.9 million clients Chick-fil-A discloses data breach after credential stuffing attacks Estée Lauder discloses data breach via Oracle E-Business flaw
When was this signal reported?
Shadow Tier lists Jun 28, 2026 as the signal date.
Which organization is connected to this signal?
Jcom is the organization connected to this public signal.
Explore JcomWhich impact area is relevant?
This signal is connected to data exposure and breach intelligence based on its reported consequences.
Explore data exposure and breach intelligenceRelated signals
Compare shared topics, actors and incident patterns before opening the full signal.
Origin Energy Discloses Data Breach Affecting 900,000 Customers
On July 28, 2026, Origin Energy, a major Australian energy company, publicly confirmed a significant data breach impacting approximately 900,000 current and former customers. The breach led to unauthorized access and exfiltration of personally identifiable information (PII), including names, addresses, dates of birth, phone numbers, account details, and partial payment information such as the last four digits of credit cards or the BSB and last three digits of bank accounts. Origin Energy first identified a potential security threat in early July 2026, which was initially not deemed credible. However, new information on July 22, 2026, confirmed a security incident had occurred, prompting immediate action and notification of authorities. An alleged hacker provided a media outlet with a sample of 50 customer records and screenshots of internal Origin Energy systems, corroborating the data exfiltration. The incident is currently under investigation by Australian authorities, including the Australian Cyber Security Centre, the National Office of Cyber Security, the Australian Federal Police, and the Office of the Australian Information Commissioner. The specific technical vector used for initial access remains undisclosed.
Related context
DoorDash Confirms Data Breach After Social Engineering Attack
DoorDash, the popular food delivery platform, publicly acknowledged a cybersecurity incident that compromised the personal information of an undisclosed number of users. The breach, which occurred on October 25, was a result of a social engineering attack targeting a company employee. This allowed an unauthorized third party to gain access to DoorDash's internal systems. The compromised data varied by individual but potentially included first and last names, phone numbers, email addresses, and physical addresses of customers, Dashers (delivery drivers), and merchants across the United States, Canada, Australia, and New Zealand. DoorDash emphasized that no sensitive financial information, such as Social Security numbers, government-issued IDs, driver's license details, bank information, or payment card data, was accessed. The company's security team identified and shut down the unauthorized access shortly after its detection, launched an internal investigation, and notified law enforcement. DoorDash has also implemented multiple security enhancements, including upgraded security systems and additional employee training programs focused on social engineering awareness. While the company has stated there is no indication the data has been misused for fraud or identity theft, affected users are advised to be cautious of unsolicited communications requesting personal information. This incident marks DoorDash's third known cybersecurity incident in six years, highlighting the persistent threat of social engineering attacks.
Related context
South Korean Diplomatic Academy Suffers Significant Data Leak Affecting 10,000 Diplomats
On July 21, 2026, the Korea National Diplomatic Academy, an institution affiliated with South Korea's Ministry of Foreign Affairs, confirmed a significant data leak impacting approximately 10,000 records of current and retired diplomats. The breach, which occurred in the academy's online education system, was discovered in early February 2026 after suspicious access was reported by a government agency. An unidentified attacker exploited a zero-day vulnerability in the server software and weaknesses in system security settings, maintaining unauthorized access from April to May 2025 until February 2026. The compromised data reportedly included names, user IDs, email addresses, encrypted passwords, job titles, and affiliated departments. While sensitive personal information such as resident registration numbers, mobile phone numbers, and home addresses were not present on the affected server, the leak of diplomat information raises concerns, especially given that the full list of diplomats and personnel at overseas missions is not publicly disclosed. The Foreign Ministry is investigating the incident and has urgently shut down the compromised system. They are operating under the assumption that a substantial volume of data was compromised, though the exact scale of the damage is still being assessed. The incident highlights the challenges in detecting sophisticated attacks that leverage previously unknown vulnerabilities.
Related context
CTIVD: AIVD en MIVD verwerken persoonsgegevens in bulkdata onrechtmatig
The Dutch intelligence services, AIVD and MIVD, have unlawfully processed personal data in bulk datasets, according to a ruling by the Committee for the Supervision of the Intelligence and Security Services (CTIVD). The report, published on July 1, 2026, states that groups of employees had unauthorized access to personal data, and large quantities of data were stored for too long. The bulk datasets, sometimes containing millions of records, include names, phone numbers, location data, social media data, and communication content, sourced from government agencies, commercially available datasets, or stolen datasets offered by criminals. The CTIVD has issued thirteen recommendations to improve the situation.
Related context
NIFTY Corporation Affected by KDDI Corporation Data Breach
NIFTY Corporation, a Japanese internet service provider, was impacted by a data breach originating from an email system provided by KDDI Corporation. Threat actors gained unauthorized access to this shared system by exploiting a vulnerability in third-party software. This led to the potential exposure of up to 14.2 million email addresses and passwords across all affected ISPs. NIFTY Corporation customers' email addresses and passwords may have been compromised.
BIGLOBE Inc. Affected by KDDI Corporation Data Breach
BIGLOBE Inc., a Japanese internet service provider, was impacted by a data breach originating from an email system provided by KDDI Corporation. Threat actors gained unauthorized access to this shared system by exploiting a vulnerability in third-party software. This led to the potential exposure of up to 14.2 million email addresses and passwords across all affected ISPs. BIGLOBE Inc. customers' email addresses and passwords may have been compromised.