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Synthient Credential Stuffing Threat Data data breach

From Breaches, in the HARD wiki · Updated
This article is about the April 2025 breach of Synthient Credential Stuffing Threat Data. For every breach, see Breaches.

The Synthient Credential Stuffing Threat Data data breach exposed 1,957,476,021 accounts in April 2025. The data taken includes passwords and email addresses.[1]

Have I Been Pwned verified it and added it to its search on 6 Nov 2025, 7 months later. It is the largest of the 618 breaches in HARD’s list.

What was exposed

Synthient Credential Stuffing Threat Data’s breach included 2 kinds of data. What each lets criminals do:

DataWhat it’s used for
PasswordsCriminals try leaked passwords on email, banking and shopping sites, because people reuse them.
Email addressesExpect scam emails that name the company to look genuine.

What to do

  1. Check whether you’re in it.Search your email address on Have I Been Pwned. It tells you which breaches it appears in, Synthient Credential Stuffing Threat Data among them, without showing the data.
  2. Change your Synthient Credential Stuffing Threat Data password.If the account still exists, sign in at Synthient Credential Stuffing Threat Data and change it.
  3. Change it anywhere you used the same one.Start with your email, then banking and shopping. Leaked passwords are tried on other sites automatically, within days.
  4. Use a password manager and two-step sign-in.A different password for every site means one breach can’t open the rest. Two-step sign-in stops a leaked password working on its own.
  5. Distrust messages that mention Synthient Credential Stuffing Threat Data.Scammers use breach data to sound genuine. Don’t click links in emails or texts about the breach; go to the site yourself.

Timeline

  • : the breach, as best it can be dated.
  • : Have I Been Pwned verifies the data and adds it to its search, 7 months later.
  • : the entry was last updated.

Similar breaches

Breaches that leaked the same kinds of data, closest in time:

See Breaches for all 618, and Updates for keeping your devices patched.

References

  1. ^ Troy Hunt. “Synthient Credential Stuffing Threat Data”, Have I Been Pwned, added 6 Nov 2025. Breach data licensed CC BY 4.0.