The usmix Combolist Gave Hackers 9,993 Ready-to-Use Login Credentials

The usmix Combolist: What HEROIC Analysts Found. HEROIC analysts identified a combolist file labeled usmix that was uploaded by a Telegram user in April 2026. The file contains 9,993 records pairing email or username combinations with plaintext passwords, along with the URLs of the sites those credentials belonged to. Why This Is Dangerous. A combolist bundles working, or once-working, username and password pairs into a single file, making it easy for anyone to run large numbers of login attempts across other websites in a short amount of time. Because the passwords were stored as plaintext, no extra effort is needed to read them. What Was Exposed: Email addresses or usernames tied to individual accounts. Plaintext passwords with no protection. The URLs of the sites those credentials originated from. Why This Matters. Combolists are a favorite tool for credential stuffing, where automated tools test the same email and password pair against dozens of other websites hoping people reused the login. If any of the 9,993 accounts in this file reused a password elsewhere, those other accounts, including banking, email, or shopping logins, could be at risk of takeover. How Combolists Work. A combolist is typically built by combining data from multiple smaller breaches or stealer infections into one large text file of combo entries, each pairing a login with a password. Criminals share and trade these files, often through channels like Telegram, and then feed them into automated tools that attempt to log into popular websites at scale. Check If You're Affected. If your email address might be part of this or a similar leak, HEROIC's free breach scanner checks it against a database of more than 400 billion leaked records, so you can find out in seconds whether your information has been exposed.