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May 11, 2011 Verified Technology

MuMaYi Data Breach

The 2011 MuMaYi (木蚂蚁) data breach occurred in May 2011 when the Discuz! community and Android application repository database of MuMaYi (mumayi.com), a leading Chinese Android app marketplace and custom ROM forum, was breached and leaked online.

127.5 Thousand
Reported Records
6
Data Types
High
Severity
Oct 10, 2026
Last updated

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Exposed Data Types

6
  • Email addresses
  • Usernames
  • Passwords
  • IP addresses
  • Dates of birth
  • Genders

Breach Details

Company NameMuMaYi
SectorTechnology
Domainmumayi.com
Breach DateMay 11, 2011
Sourcemumayi.com(opens in a new tab)synscan.net(opens in a new tab)ransomlook.io(opens in a new tab)
Last updatedOctober 10, 2026

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About This Breach

What information was affected in the MuMaYi incident?

The leaked member table (mumayicdb_members) encompasses developers, modders, and mobile app users. The incident compromised records for 127,515 unique individuals, exposing:

  • Account Identifiers: Community usernames and numerical identifiers (uid).
  • Contact Credentials: Canonical email addresses across domestic Chinese providers (qq.com, 163.com, 126.com, sina.com, sohu.com) and international mail services.
  • Authentication Secrets: MD5 password hashes and security question tokens (secques).
  • Network Telemetry: Registration IP addresses (regip) and last login IP addresses (lastip).
  • Demographic Records: Dates of birth (bday) and gender.

How many accounts were affected?

Rigorous RFC canonical parsing and deduplication confirmed 127,515 unique valid email addresses.

Technical analysis and security risks

The exposure stems from an exploited vulnerability in the Discuz! forum installation. MD5 password hashes are vulnerable to modern GPU-based cracking, facilitating credential-stuffing campaigns across personal webmail and related platform accounts.

Recommended actions for affected users

Former members of MuMaYi should:

  • Immediately update passwords across any active email or web accounts where their old forum password was reused.
  • Enable two-factor authentication (2FA) across all critical services.

Verification and editorial method

LeakData compares the incident name, date, affected-record count, and exposed data types with accessible sources. Unverified fields are not presented as facts, and records are updated when new evidence becomes available.

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