Cit0day
HIGH RISKData breach — November 2020
In November 2020, a collection of more than 23,000 allegedly breached websites known as Cit0day were made available for download on several hacking forums. The data consisted of 226M unique email address alongside password pairs, often represented as both password hashes and the cracked, plain text versions. Independent verification of the data established it contains many legitimate, previously undisclosed breaches. The data was provided to HIBP by dehashed.com.
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What happened in the Cit0day data breach?
In November 2020, a collection of more than 23,000 allegedly breached websites known as Cit0day were made available for download on several hacking forums. The data consisted of 226M unique email address alongside password pairs, often represented as both password hashes and the cracked, plain text versions. Independent verification of the data established it contains many legitimate, previously undisclosed breaches. The data was provided to HIBP by dehashed.com.
The exposed data included 2 types of personal information. Because passwords were exposed, users who reused their password on other sites are at particular risk. Learn more about what a data breach means for you.
Quick answer — was Cit0day hacked?
Yes. Cit0day was breached in November 2020. The breach exposed 226,883,414 records including email addresses, passwords. If your email was involved, your data may still be at risk today. Check if you were affected.
Why was the Cit0day breach so dangerous?
The Cit0day breach exposed 226,883,414 records — that is 226.9M people whose personal data is now circulating on the dark web. The combination of email addresses, passwords makes this a high-risk breach that requires immediate action.
Because passwords were exposed, attackers can use credential stuffing to automatically test your Cit0day password against hundreds of other websites. If you reused your password anywhere, those accounts are now at risk. Read more about what happens to your data after a breach.
Don't wait to find out — check if your email was exposed in this breach now.
What data was stolen in the Cit0day 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
Is the Cit0day breach still dangerous in 2026?
Yes. Stolen data from the Cit0day 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 2020 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 Cit0day 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 Cit0day breach
Approximately 226,883,414 user records were exposed in the Cit0day breach in November 2020.
Yes. Leaked credentials are actively used in credential stuffing attacks years after a breach. If you reused your Cit0day 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 Cit0day dataset and tell you instantly whether your email was exposed and what data was taken.
Change your Cit0day 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 Cit0day breach?
The Cit0day data breach affected approximately 226,883,414 users who had accounts with the service. With 226.9M records exposed, this is one of the larger breaches tracked in our database of 970+ known breaches.
If you ever created an account with Cit0day 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 Cit0day breach
Change your Cit0day password immediately
Go to Cit0day 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 Cit0day 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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