Email Service Users Exposed: The QQ Mail Breach Leaked 2.7M Records

In August 2025, security analysts found a large dataset posted on a well-known hacking forum. The data was tied to QQ Mail, a popular email service run by Tencent and widely used across China. The breach affected 2,715,895 user accounts and the records included email addresses, phone numbers, usernames, and physical addresses. The data was posted on August 22, 2025, meaning it was available for anyone to download and use within hours of being discovered by our team.

Why This Is Dangerous

Email accounts are not just for reading messages. They are the master key to almost everything else online. With a victim's QQ Mail address, phone number, and username all in one place, attackers can try to reset passwords on banking apps, social media, and shopping sites. They can call the victim's phone and pretend to be a bank or government agency because they already know the victim's real name and email. They can also build highly personal phishing emails that look completely legit because the attackers already know so much about the target. The combination of email, phone, and username in a single dataset is particullarly dangerous.

What Was Exposed in the QQ Mail Breach

• Email addresses
• Phone numbers
• Usernames
• Physical addresses

Why This Matters

When your phone number and email address are both in the same leak, attackers can do a lot more damage than with just one or the other. They can try SIM swap attacks, where they convince your mobile carrier to transfer your number to a device they control. Once they have your number, they can bypass two-factor authentication on your most important accounts. They can also use your personal details for identity theft, open credit accounts in your name, or sell your information to other criminals. The 2.7 million record scale means this data will circulate on the dark web for years.

How Database Breaches Work

A database breach happens when an attacker gains access to the backend systems of a website or app and copies out the stored user data. This can happen through a security vulnerability in the site's code, a misconfigured server, or stolen admin credentials. Once the attacker has the database, they can download it in minutes. The stolen data is then often sold on hacking forums or posted publicly to build a reputation in the criminal community. In this case, the QQ Mail dataset appeared on a prominant hacking forum, suggesting it was shared deliberately to maximize exposure.

Check If You Are Affected

HEROIC offers a free breach scanner that searches over 400 billion leaked records to find out if your email address or personal data has been exposed. If your information is in this QQ Mail leak or any other known breach, you will receive an immediate alert. Visit HEROIC.com to run your free scan and take action before someone else does.