T-Mobile 2021 Data Breach

Critical Severity 77 million records affected
CompanyT-Mobile
Breach DateAugust 1, 2021
Disclosure DateAugust 15, 2021
Records Affected77 million

The August 2021 T-Mobile breach exposed highly sensitive data for over 77 million people, including Social Security numbers, driver's license information, and account PINs.

What Happened

A 21-year-old hacker exploited an unprotected router to gain access to T-Mobile's internal network. From there, he accessed over 100 servers containing customer data.

The attacker later told media that T-Mobile's security was "awful" and that gaining access was trivially easy. This was at least the fifth major breach T-Mobile had suffered since 2018.

What Data Was Exposed

  • Social Security numbers
  • Driver's license numbers
  • Government ID information
  • Account PINs
  • Names and addresses
  • Dates of birth
  • Phone numbers
  • IMEI numbers

Who Is Affected

Over 77 million current, former, and prospective T-Mobile customers, including Metro by T-Mobile and Sprint users.

How to Check If You Were Affected

T-Mobile sent notifications to affected customers. You can also contact T-Mobile support to verify.

What You Should Do Now

  1. Change your T-Mobile PIN immediately
  2. Freeze your credit at all three bureaus
  3. Enable account takeover protection with T-Mobile
  4. Sign up for free identity protection offered by T-Mobile
  5. Watch for SIM swap attacks
  6. Monitor your credit reports

Last updated: January 13, 2026