Collection #1
HIGH RISKData breach — January 2019
In January 2019, a large collection of credential stuffing lists (combinations of email addresses and passwords used to hijack accounts on other services) was discovered being distributed on a popular hacking forum. The data contained almost 2.7 billion records including 773 million unique email addresses alongside passwords those addresses had used on other breached services. Full details on the incident and how to search the breached passwords are provided in the blog post The 773 Million Record "Collection #1" Data Breach.
search Check if you were affected — freeData exposed in this breach
What happened in the Collection #1 data breach?
In January 2019, a large collection of credential stuffing lists (combinations of email addresses and passwords used to hijack accounts on other services) was discovered being distributed on a popular hacking forum. The data contained almost 2.7 billion records including 773 million unique email addresses alongside passwords those addresses had used on other breached services. Full details on the incident and how to search the breached passwords are provided in the blog post The 773 Million Record "Collection #1" Data Breach.
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 Collection #1 hacked?
Yes. Collection #1 was breached in January 2019. The breach exposed 772,904,991 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 Collection #1 breach so dangerous?
The Collection #1 breach exposed 772,904,991 records — that is 772.9M 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 Collection #1 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 Collection #1 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 Collection #1 breach still dangerous in 2026?
Yes. Stolen data from the Collection #1 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 2019 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 Collection #1 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 Collection #1 breach
Approximately 772,904,991 user records were exposed in the Collection #1 breach in January 2019.
Yes. Leaked credentials are actively used in credential stuffing attacks years after a breach. If you reused your Collection #1 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 Collection #1 dataset and tell you instantly whether your email was exposed and what data was taken.
Change your Collection #1 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 Collection #1 breach?
The Collection #1 data breach affected approximately 772,904,991 users who had accounts with the service. With 772.9M records exposed, this is one of the larger breaches tracked in our database of 970+ known breaches.
If you ever created an account with Collection #1 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 Collection #1 breach
Change your Collection #1 password immediately
Go to Collection #1 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 Collection #1 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.
searchCheck all my breaches — freeOther major breaches
Was my email hacked?
Check if your email is compromised in seconds. Free, private, no signup. Scan 12 billion+ records across 970+ known breaches.
search Check my email now — it's freeNo signup required · Results in under 5 seconds · Your data is never stored