China Software Developer Network Data Breach
What Happened
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.
Compromised Data
Recommended Actions
Change Your Password
If you haven’t already changed the password affected by this breach, do so immediately on every account where it was used.
Enable Two-Factor Authentication
Wherever 2FA is supported, add an extra layer of security to your account.
Use a password manager to generate and store strong, unique passwords for all your accounts. 1Password helps protect your data with industry-leading security.
Try 1PasswordBreach Overview
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Affected Accounts:
6.4 million
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Breach Occurred:
December 2011
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Added to HIBP:
27 Nov 2025
Recommended Actions
Change Your Password
If you haven’t already changed the password affected by this breach, do so immediately on every account where it was used.
Enable Two-Factor Authentication
Wherever 2FA is supported, add an extra layer of security to your account.
Use a password manager to generate and store strong, unique passwords for all your accounts. 1Password helps protect your data with industry-leading security.
Try 1Password