About 1.96 billion unique emails sat in this 2025 credential-stuffing compilation — not a hack of Synthient the company. Check whether your address is in that file, then treat any reused password as the first job.
Quick answer — was Synthient Credential Stuffing Threat Data breached?
No — this page is not a single-company login breach. It is a 2025 threat-intelligence compilation of about 1.96 billion unique email addresses and on the order of 1.3 billion unique passwords gathered from credential-stuffing lists. A match means your address appeared in that compiled file. It is not the Synthient stealer-log row. Check if you were affected.
This catalog row is a 2025 threat-intelligence compilation — not a hack of a company called Synthient, and not a Gmail, Microsoft, or bank disclosure. During 2025 the firm Synthient aggregated email-and-password pairs from credential-stuffing lists already circulating on forums, chat channels, and similar markets. After de-duplication, this lookup lists about 1.96 billion unique email addresses plus passwords. Public analysis of the same corpus put unique passwords on the order of 1.3 billion. The pairs typically came from earlier site breaches that stored passwords badly or that had already been cracked. Attackers feed those lists into bots that try the same login on other sites.
A match does not name the original shop, game, or forum. It means that address — and typically a password pair — sat in a stuffing kit assembled from many older dumps. If you still use that password anywhere, a bot can try it on email, shopping, and banking logins without ever “hacking Synthient.” This is the same class of problem as Collection #1: reused passwords, not one new company failure. Changing a password only on a site you do not remember does not retire the same string on email.
This catalog’s date is 11 April 2025. That is a collection-window label, not the day one company was breached. Public catalogs added the row on 6 November 2025. It is a separate file from Synthient Stealer Log Threat Data, which loaded earlier (21 October 2025) and comes from malware on devices, not from combo lists. Industry-standard breach data sources list only email addresses and passwords on this row. Learn more about what a data breach means for you.
A match does not name the original shop, game, or forum. It means that address — and typically a password pair — sat in a stuffing kit assembled from many older dumps. If you still use that password anywhere, a bot can try it on email, shopping, and banking logins without ever “hacking Synthient.” This is the same class of problem as Collection #1: reused passwords, not one new company failure. Changing a password only on a site you do not remember does not retire the same string on email.
Yes, if any password that sat in that file is still in use. Stuffing lists are copied, re-sorted, and fed to bots for years. As of 2026 the file is a snapshot of lists that were already circulating. It does not expire. You cannot log into Synthient to reset an account. Unique passwords and an authenticator-app second factor are the work.check whether your email was exposed in this breach.
Email addresses — used for phishing attacks and credential stuffing against your other accounts
Passwords — can be used to access your accounts directly or cracked to reveal your actual password
2010s–2024
Site breaches and cracked password files are bundled into credential-stuffing lists and recirculated on forums and chat channels
2025
Synthient aggregates and de-duplicates those lists as part of a larger threat-data corpus; public analysis later describes stuffing lists and stealer logs as two different kinds of file
11 April 2025
This catalog’s dated label for the stuffing row — a collection window, not a single-company intrusion date
21 October 2025
The separate stealer-log row is added to public catalogs first — see Synthient Stealer Log Threat Data
6 November 2025
This stuffing compilation is added as its own catalog row: about 1.96 billion unique emails and on the order of 1.3 billion unique passwords
2025–2026
Copies remain in stuffing toolkits; leftover reused passwords from the file still unlock other sites
Yes, if any password that sat in that file is still in use. Stuffing lists are copied, re-sorted, and fed to bots for years. As of 2026 the file is a snapshot of lists that were already circulating. It does not expire. You cannot log into Synthient to reset an account. Unique passwords and an authenticator-app second factor are the work.
Email addresses in a stuffing list do not expire as phishing targets. A unique password plus two-factor authentication is what ages this row out of your life. Learn how long stolen data stays dangerous.
Synthient is a threat-intelligence project that collected lists attackers already pass around. It is not a website you signed up for, and it did not send a classic “we were hacked” customer letter. There is no Synthient password to reset. The name on the row is the compiler, not the original leak.
A credential-stuffing list is a combo list: email plus password, often already in usable form, built so a bot can try thousands of logins a minute. The original source may have been a forgotten forum, a 2010s consumer app, or a dump that was never announced. Public write-ups of Synthient’s pipeline describe Telegram channels, forums, and social posts as the places those lists were scooped from — not a claim that EmailLeaked sits on exclusive dark-web feeds.
This row is not Synthient Stealer Log Threat Data. Stealer logs are typed or saved on an infected device and usually include the site where the password was entered. This stuffing row does not tell you that site. It is also not a new Gmail or Microsoft breach. Headlines that treat a 2025 compilation as “your inbox was just hacked” collapse two different stories. And it is not Collection #1 — that is the January 2019 combolist — though both are the same class of problem.
If your address is in the compiled file, EmailLeaked shows a named Synthient Credential Stuffing Threat Data match the same way it shows a named company incident. The row is a lookup against industry-standard breach data sources. We do not claim exclusive ownership of Synthient’s corpus, we did not compile the lists, and we do not crawl hidden markets live.
A match is not proof someone opened a session this week. It is evidence that the address — and typically a password pair from some earlier leak — appeared in a stuffing kit that public catalogs loaded in November 2025. A miss is a snapshot of the records we can search today. We do not keep the address you type into the checker. Hosting logs and a privacy-oriented analytics beacon can still record that the page was visited.
If you want the name decoded in one place, use What is Synthient? Breach names explained. For the attack these lists are built for, see what is credential stuffing. For the response order, use what to do after a data breach. To test a reused password without sending the full password, use the password leak checker.
Confirm the match and which Synthient file it is
Run the email check if you need the named incidents in one list. This row is the stuffing compilation (emails and passwords). The malware-log file is Synthient Stealer Log Threat Data.
Check this email — freeTreat any reused password as public
You cannot log into Synthient. Change the password on your email account and on every site that shared it. Then check whether that password appears in known leaks without sending the password itself.
Turn on two-factor authentication
Start with email. An authenticator app is stronger than a text-message code. A stuffing bot that has the compiled password still fails if the second factor is not sitting on a leaked phone number.
Follow the after-breach playbook
Use the first-hour and 24-hour lists, then the password playbook. Walk the account security checklist so recovery email, sessions, and leftover logins get a pass.
Open the after-breach playbookCompare how public checkers differ
A second lookup does not change the 2025 compilation. It can show you how different public indexes present the same named dataset.
Read the checker comparisonClose leftover accounts that reused the password
There is no Synthient login to delete. After you retire the reused password, close leftover site accounts so that old string stops sitting around. That is hygiene, not a way to un-leak the compilation.
Browse delete-account guidesBreach pages are built from structured breach records and reviewed for practical risk guidance by EmailLeaked. Risk labels reflect exposed data types and are intended to help readers prioritise action.
Sources
Last updated: September 2026
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