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Confirmed breach

Sierra Management Group data breach

USUnited States

Sierra Management Group (United States) notified the California Attorney General of a data breach on 29 June 2026.

Status
Confirmed breach
People affected
Not reported yet
Reported
29 June 2026

What was exposed

The register’s list does not say what was exposed; the notice it links to (under Sources) usually does.

Before the notice: the ransomware gang Genesis named Sierra Management Group on its leak site on 7 March 2026, 114 days before this was reported. Matched by the organisation’s name: the notice itself does not say who the attacker was.

What the letter says

We have not read this letter yet.

Got a letter or email about this breach? Check it is real →

Read the letter (PDF), as filed with the California Attorney General.

Sources

Official notices are read by code from the regulator’s own register. More notices to California. · Corrections and changes

If Sierra Management Group had your data

  1. Look for Sierra Management Group’s own notice or letter: it should say what of yours was involved. Keep it.
  2. The register’s list does not say what was exposed; the notice it links to (under Sources) usually does. If Sierra Management Group has a password of yours, change it now to be safe.
  3. Expect scams that use your details: calls, texts or emails pretending to be Sierra Management Group, your bank or the police. Never give codes or passwords, never approve a sign-in you did not start, never move money.

One email to confirm first. We use your address only for this alert, and one click deletes it.

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From the data breach tracker: official notices, breach databases and the news, every fact with its source. Open data (CC BY 4.0) · How the tracker works · Official registers · Corrections and changes · Found a mistake? Tell us and we correct it.