Synthient Stealer Log Threat Data data breach

Breach date: 2025-04-11. Added to this index: 2025-10-21. Accounts affected: about 183M. Domain: not listed.

What happened

During 2025, Synthient aggregated billions of records of "threat data" from various internet sources. The data contained 183M unique email addresses alongside the websites they were entered into and the passwords used. After normalising and deduplicating the data, 183 million unique email addresses remained, each linked to the website where the credentials were captured, and the password used. This dataset is now searchable in HIBP by email address, password, domain, and the site on which the credentials were entered.

Breach data sourced from Have I Been Pwned, used under CC BY 4.0. Additional breach metadata provided by XposedOrNot. DataExposed is an independent service and is not affiliated with or endorsed by either.

What was exposed

  • Email addresses: The email address you used to register or log in. It is the most common field in breaches because it doubles as your username on most sites.
  • Passwords: The secret you use to sign in, stored by the breached service either in plain text, in a scrambled form called a hash, or encrypted. How it was stored decides how quickly it can be recovered.

What to do now

  1. Check whether your own address is in this dataset with the free email breach check.
  2. Change the password on this service and every other site where you used the same password.
  3. Turn on two-factor authentication on your email account first, because it is the reset path for everything else.
  4. Treat calls and messages that quote real details about you as hostile until you verify them another way.

Frequently asked questions

What data was leaked in the Synthient Stealer Log Threat Data breach?

The Synthient Stealer Log Threat Data breach exposed Email addresses, Passwords. About 183M accounts were affected.

Was I affected by the Synthient Stealer Log Threat Data breach?

Run the free email breach check with the address you used on that service. It will tell you whether your address appears in this dataset.

What should I do about the Synthient Stealer Log Threat Data breach?

Change the password on that account and everywhere you reused it, then turn on two-factor authentication. Passwords from this breach are traded and tried automatically against other sites.

Next steps