China Software Developer Network data breach: 6.4M accounts exposed
Severity: high · Patch status: no-fix-needed · Since 2025-11-27
In 2011, the China Software Developer Network (CSDN) suffered a data breach that exposed over 6M user records. The data included email addresses alongside usernames and plain text passwords. Exposed data: email addresses, passwords, usernames. The breach dates from Dec 21, 2011; Have I Been Pwned loaded it on Nov 27, 2025.
What to do
- If you had a China Software Developer Network account, change its password and the password of any other account that reused it.
- Turn on multi-factor authentication wherever it is offered.
- Check whether your addresses are in this breach at https://haveibeenpwned.com.
- Expect targeted phishing that quotes the leaked details; verify any unexpected contact out of band.
Sources
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