T-Mobile USA

Disclosed Aug 24, 20215 years agoConfirmed

Official notice

What is known

People affected	Not stated in the sources we have
Disclosed	Aug 24, 2021
Discovered	Aug 17, 2021
Happened	Jul 22, 2021
Attack	Hacking
Data exposed	Not stated
Sector	Telecom · US
Status	Confirmed

Sources

Source	Kind
California Attorney General breach notice: T-Mobile USAoag.ca.gov · Official notice	Official notice
Washington Attorney General breach notice: T-Mobile USAatg.wa.gov · Official notice	Official notice
Oregon DOJ breach notice: T-Mobile USAjustice.oregon.gov · Official notice	Official notice

Notices filed

Where	Filed	People
Washington AGresidents of WA	Aug 24, 2021	2,079,648
California AGresidents of CA	Aug 25, 2021
Oregon DOJresidents of OR	Aug 27, 2021

Other breaches at T-Mobile USA

Breach	Disclosed	Attack	Sector	Status	Affected
Disclosed Jan 19, 2023Jan 19, 20233 years agoHacking	Jan 19, 20233 years ago	Hacking	Telecom	Confirmed	Unknown
Disclosed Mar 10, 2020Mar 10, 20206 years ago	Mar 10, 20206 years ago	Not stated	Telecom	Confirmed	1,027
Disclosed Oct 1, 2015Oct 1, 201510 years ago	Oct 1, 201510 years ago	Not stated	Telecom	Confirmed	Unknown

History of this record

2026-09-25 · attack: unknown to hacking · backfill source
2026-09-25 · disclosed: 2021-08-25 to 2021-08-24 · backfill source
2026-09-25 · discovered: empty to 2021-08-17 · backfill source
2026-09-25 · added · backfill source

First seen 2026-09-25 (California AG), confirmed by California AG. Record counts are as reported. Not legal advice.

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