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Data breaches → Synthient Stealer Log Threat Data

Was your data in the Synthient Stealer Log Threat Data breach?

2025 · ~182,962,095 accounts exposedCritical severity · 10/10

Synthient Stealer Log Threat Data suffered a data breach in 2025 that exposed around 182,962,095 accounts. If you had an account, some of your personal data may be circulating in leaked databases. The fastest way to know is to check your own email — free, in about 30 seconds, no password required.

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 details sourced from Have I Been Pwned, the industry-standard breach database. Risk analysis by Nullivo.

What was exposed, and why it matters

Not all breaches carry the same risk — what matters is which fields leaked. Here is what the Synthient Stealer Log Threat Data breach exposed and what each item actually enables:

Passwords

Attackers replay leaked passwords across other sites (“credential stuffing”). Because most people reuse passwords, one leak often unlocks email, shopping and banking accounts elsewhere.

Email addresses

Puts you on spam and phishing lists, and confirms to attackers that you hold an account with this service — which makes impersonation emails more believable.

What to do if you were affected

These steps are ordered for this specific breach — the most urgent action given what leaked comes first.

  1. Passwords: Change this password everywhere you have reused it, starting with your email account — whoever controls your email can reset everything else.
  2. Email addresses: Treat any message referencing this service with suspicion, and never act on links in unexpected emails.
  3. Check whether your own email appears in this breach — run a free scan to confirm before you spend time on the steps above.

How urgent is this now?

This breach is recent, so the data is actively traded and the risk is at its highest right now.

Passwords are the reason breach age matters less than people expect. Leaked credentials are compiled into wordlists that get tried against new services for years afterwards, so a password exposed here is unsafe to use anywhere, ever again.

Remember: a breach can't be "un-leaked" — once a database is out, it exists in countless copies. The goal is to make the leaked data useless: change what can be changed, lock down what can't, and remove what has been republished.

Check if your email was exposed.Nullivo's free scan checks your own verified email against known breaches — including Synthient Stealer Log Threat Data — in 30 seconds. No password, no signup, and we only ever scan your own email. Run your free scan →

Frequently asked questions

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

The Synthient Stealer Log Threat Data breach exposed passwords, email addresses. Attackers replay leaked passwords across other sites (“credential stuffing”). Because most people reuse passwords, one leak often unlocks email, shopping and banking accounts elsewhere.

How many people were affected by the Synthient Stealer Log Threat Data breach?

Around 182,962,095 accounts were exposed, making it one of the largest breaches ever recorded.

What should I do if I had a Synthient Stealer Log Threat Data account?

Change this password everywhere you have reused it, starting with your email account — whoever controls your email can reset everything else. You can check whether your own email appears in this breach with a free Nullivo scan — no password required.

Breaches that exposed similar data

If the Synthient Stealer Log Threat Data breach affected you, these breaches exposed comparable information — worth checking too, since leaked datasets are routinely combined.

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