Reported by 1 outlet
KDDI Data Breach Exposes Up to 14.2 Million Email Logins Across Six Japanese ISPs
Why this score
- Breadth
- 0.50 / 2.0 · 1 source
- Authority
- 1.80 / 2.0 · best outlet weight
- Severity
- 0.50 / 5.0 · CVSS + content signals
- Velocity
- 0.00 / 2.0 · updates in 48h
- Pickup speed
- 0.00 / 0.6 · time to second source
- Recency
- × 0.00 temporal multiplier
- Community
- + 0.00 / 1.5 · reddit signal
- Score
- 0.0 / 10 = base × recency + community
Timeline
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original reporting
KDDI Data Breach Exposes Up to 14.2 Million Email Logins Across Six Japanese ISPs
bleepingcomputer.com · 108d ago · June 28th, 2026
Japanese telecommunications giant KDDI Corporation disclosed a data breach in which threat actors gained access to its email infrastructure, potentially exposing the email addresses and passwords of up to 14.2 million customers across six internet service providers.
KDDI discovered the compromise on June 17 and says attackers exploited a vulnerability in an unnamed third-party software component. The affected ISPs — STNet, JCOM, Chubu Telecommunications, NIFTY Corporation, and BIGLOBE — were notified starting June 17, along with Japan's Personal Information Protection Commission and the Ministry of Internal Affairs and Communications.
KDDI states that some passwords were stored in hashed and/or encrypted form, but did not disclose what percentage were stored in plaintext or which hashing algorithm was used. The company advises affected customers to reset their email passwords immediately and enable two-factor authentication where available. The investigation is ongoing, and the exact number of compromised accounts has not yet been determined.