NemoWeb
MEDIUM RISKData breach — September 2016
In September 2016, almost 21GB of data from the French website used for "standardised and decentralized means of exchange for publishing newsgroup articles" NemoWeb was leaked from what appears to have been an unprotected Mongo DB. The data consisted of a large volume of emails sent to the service and included almost 3.5M unique addresses, albeit many of them auto-generated. Multiple attempts were made to contact the operators of NemoWeb but no response was received.
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What happened in the NemoWeb data breach?
In September 2016, almost 21GB of data from the French website used for "standardised and decentralized means of exchange for publishing newsgroup articles" NemoWeb was leaked from what appears to have been an unprotected Mongo DB. The data consisted of a large volume of emails sent to the service and included almost 3.5M unique addresses, albeit many of them auto-generated. Multiple attempts were made to contact the operators of NemoWeb but no response was received.
The exposed data included 2 types of personal information. Learn more about what a data breach means for you.
Quick answer — was NemoWeb hacked?
Yes. NemoWeb was breached in September 2016. The breach exposed 3,472,916 records including email addresses, names. This breach has been independently verified. If your email was involved, your data may still be at risk today. Check if you were affected.
Why was the NemoWeb breach so dangerous?
The NemoWeb breach exposed 3,472,916 records — that is 3.5M people whose personal data is now circulating on the dark web. The combination of email addresses, names makes this a medium-risk breach that should be addressed promptly.
Don't wait to find out — check if your email was exposed in this breach now.
What data was stolen in the NemoWeb breach?
Email addresses — used for phishing attacks and credential stuffing against your other accounts
Names — used to build profiles and target you with personalised scams
Is the NemoWeb breach still dangerous in 2026?
Yes. Stolen data from the NemoWeb breach remains dangerous years after the incident. Research shows that over 65% of stolen credentials from older breaches have never been changed by the account holders. Attackers routinely compile data from multiple breaches to build complete profiles, and credentials from 2016 are still actively used in credential stuffing attacks today.
Personal information like email addresses, phone numbers, and dates of birth never expire. Even if you changed your NemoWeb password, the other exposed data can be combined with information from other breaches to target you. Learn more about how long stolen data stays dangerous.
Frequently asked about the NemoWeb breach
Approximately 3,472,916 user records were exposed in the NemoWeb breach in September 2016.
Yes. Leaked credentials are actively used in credential stuffing attacks years after a breach. If you reused your NemoWeb password elsewhere and haven't changed it, those accounts remain at risk today.
Enter your email in the free checker on EmailLeaked. We scan 12 billion+ breach records including the full NemoWeb dataset and tell you instantly whether your email was exposed and what data was taken.
Change your NemoWeb password immediately, change any other account where you used the same password, enable two-factor authentication on all important accounts, and monitor for phishing emails over the next 90 days.
Who was affected by the NemoWeb breach?
The NemoWeb data breach affected approximately 3,472,916 users who had accounts with the service. While not the largest breach on record, it still represents a significant number of compromised accounts in our database of 970+ known breaches.
If you ever created an account with NemoWeb or used their services, your data may have been included in this breach. Check your email now to find out. You can also read our guide on what to do immediately after a data breach.
If your email was in the NemoWeb breach
Change your NemoWeb password immediately
Go to NemoWeb and change your password right now. Use a strong, unique password that you have never used anywhere else.
Change any account sharing that password
If you used the same password on other sites, change it on every one of them. Attackers test stolen credentials on hundreds of popular sites within hours.
Enable two-factor authentication
Turn on 2FA on NemoWeb and every important account. Even if your password is known, attackers cannot get in without the second factor.
Check your other accounts for this breach
Run a full email check to see every breach your email appears in — not just this one.
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