MyRecon OSINTSynthient Credential Stuffing Threat Data
On 11 April 2025, Synthient Credential Stuffing Threat Data was breached. 1,957,476,021 accounts were exposed, including email addresses, passwords. MyRecon rates it 84/100 — critical. That is roughly everyone in India.
What happened
During 2025, the threat-intelligence firm Synthient aggregated 2 billion unique email addresses disclosed in credential-stuffing lists found across multiple malicious internet sources. Comprised of email addresses and passwords from previous data breaches, these lists are used by attackers to compromise other, unrelated accounts of victims who have reused their passwords. The data also included 1.3 billion unique passwords, which are now searchable in Pwned Passwords. Working to turn breached data into awareness, Synthient partnered with HIBP to help victims of cybercrime understand their exposure.
Breach description from Have I Been Pwned, used under a CC BY 4.0 licence.
Who was behind it
No party has been publicly confirmed as responsible, and this page will not name one. Most breaches are never formally attributed: data surfaces on a forum or inside a combined dump long after the intrusion, and the trail back to a specific actor is rarely made public. Where a group has claimed responsibility it is usually named in the account above — that claim is theirs, not a finding of ours.
What was exposed, and why it matters
- Email addressesThe address becomes a confirmed, active target — expect more phishing, better aimed.
- PasswordsAnyone reusing this password elsewhere has those accounts exposed too — credential stuffing is automated and tries them all within days.
What to do if you were in it
- Change this password anywhere you reused it, starting with your email account — that is the one that can reset all the others.
- Expect better-aimed phishing. A message that already knows your name and where you have an account is the whole point of a breach like this.
Questions people ask about this breach
Was my email address in the Synthient Credential Stuffing Threat Data breach?
Enter it in the box at the top of this page. MyRecon checks it against this breach and every other one on record, and the address is never stored.
What data was leaked in the Synthient Credential Stuffing Threat Data breach?
email addresses, passwords. Each one is explained above, along with what it means for the person it belongs to.
When did it happen, and when did it become public?
The breach is dated 11 April 2025. It was published to Have I Been Pwned on 6 November 2025, a gap of 209 days during which the data was already out.
Is the Synthient Credential Stuffing Threat Data breach real?
Yes. Have I Been Pwned lists it as verified, meaning the data was checked against the source rather than taken on trust.
How many people were affected?
1,957,476,021 accounts. That is roughly everyone in India. That is accounts rather than people — one person often has several.
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Severity is scored by MyRecon from the number of accounts, the sensitivity of the specific fields exposed, and whether the breach is confirmed — not by a language model. The description above is quoted from Have I Been Pwned; the analysis around it is ours.