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May 16, 2026 Verified Sensitive Record Telecommunications

KDDI ISP 2026 Data Breach

The KDDI ISP 2026 data breach resulted from exploitation of a third-party software flaw in the shared email platform KDDI developed for internet service providers.

12.2 Million
Affected People
2
Data Types
Critical
Severity
Yes
Verification

Exposed Data Types

2
Email addresses
Passwords

Additional Information

Added DateJuly 26, 2026
Breach DateMay 16, 2026
Domainkddi.com
SourceOfficial notices from affected institutions
Last Content UpdateJuly 29, 2026

Verification and editorial method

LeakData compares the incident name, date, affected-record count, and exposed data types with accessible sources. Unverified fields are not presented as facts, and records are updated when new evidence becomes available.

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Company Information

Company NameKDDI Corporation
SectorTelecommunications
CountryJapan
Websitekddi.com

Risk Level

Critical

The reported impact exceeds 1 million and falls within the critical severity band.

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