China Software Developer Network data breach (2011): was your email exposed?
China Software Developer Network (csdn.net) suffered a data breach in December 2011 that exposed around 6 million accounts. The leaked records included email addresses, passwords and usernames. Check whether your email was caught up in it — and lock down your accounts before the data is misused.
Check if my email was exposed — free →What happened in the China Software Developer Network breach?
China Software Developer Network (csdn.net) was hit by a data breach dated December 2011, exposing around 6 million accounts. Incidents like this happen when attackers break into a company’s user database, or when a misconfigured server or third-party partner leaks it — and the stolen records then spread among other criminals.
The exposed records included email addresses, passwords and usernames. Leaked data doesn’t simply disappear: it gets copied, sold and re-posted across breach forums and dark-web markets for years. That’s why your information from the China Software Developer Network breach can still be abused long after the original incident — and why checking your exposure and locking down your accounts matters even now.
What data was exposed in the China Software Developer Network breach?
The China Software Developer Network breach exposed email addresses, passwords and usernames. The more of these are tied to you, the more ways an attacker can impersonate you or break into your other accounts.
How the leaked China Software Developer Network data can be used against you
Because the China Software Developer Network breach exposed email addresses, passwords and usernames, the leaked passwords let attackers try the same login on your other accounts (credential stuffing), so any site where you reused it is at risk; and your email address becomes a target for convincing phishing, often referencing this very breach to look legitimate.
How to check if you were affected
The leaked records themselves aren’t published openly, so the way to know is to check your email against known breach and dark-web databases. Our free tool does exactly that in a few seconds — no account needed.
Check my email against known breaches — free →What to do if your China Software Developer Network account was breached
These steps are prioritized for exactly the kind of data the China Software Developer Network breach exposed.
Reset your China Software Developer Network password now, and change it on every other account where you used the same one. Reused passwords are how a single breach turns into a chain of account takeovers, so give each important account its own strong password (a password manager makes this painless).
Add 2FA — ideally an authenticator app or a passkey rather than SMS — to your email, banking and other important accounts, so a stolen password alone can’t get in.
Scammers reference real breaches to sound credible, so treat any email mentioning China Software Developer Network with suspicion, and never use a password-reset link you didn’t request — go to the site directly instead.
Leaked data is resold for years, so a one-time clean-up isn’t enough. Ongoing breach and dark-web monitoring tells you the moment your details reappear, so you can act before an account is misused.
The China Software Developer Network breach, answered
Was my email in the China Software Developer Network breach?
You can find out in seconds with our free breach and dark-web check — enter your email and it tells you whether it appears in the China Software Developer Network breach and other known incidents.
When did the China Software Developer Network breach happen?
The China Software Developer Network data breach is dated December 2011 and exposed roughly 6 million accounts. Note that breached data often surfaces and is resold long after the original date.
What data was exposed in the China Software Developer Network breach?
The exposed records included email addresses, passwords and usernames. Around 6 million accounts were affected.
What should I do after the China Software Developer Network breach?
Change your China Software Developer Network password and any reused passwords, turn on two-factor authentication, watch for phishing that references China Software Developer Network, and monitor whether your details resurface on the dark web.
Was your email in the China Software Developer Network breach?
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