The a-topmail.at Leak Could Unlock More Than Just Your Email

HEROIC analysts found a combolist titled "a-topmail.at - 584 emails" uploaded to Telegram on June 10, 2026. The file contains 584 records of topmail.at email addresses paired with plaintext passwords and associated URLs. Why This Is Dangerous: Because this list is filtered down to a single email domain, every one of the 584 credential pairs is aimed at a real, working inbox. With passwords stored in plaintext, an attacker can move straight from download to login attempt with no extra steps in between. What Was Exposed: The a-topmail.at file lists three fields per record. - topmail.at email addresses - Plaintext passwords - URLs associated with each account Why This Matters: An email inbox is often the master key to a person's other accounts, since password reset links usually go there first. If an attacker logs into one of these 584 accounts, they can potentially chain their way into banking, shopping, or social media logins tied to the same password, especially if that password was reused, a risk that runs from simple credential stuffing all the way to account takeover and financial fraud. How a Combolist Like This Works: Domain-specific combolists like this one are created by sorting a larger batch of leaked credentials down to addresses from a single email provider. Attackers do this because a targeted list is easier to work with and often more valuable to buyers who want to focus on one type of account, and these curated files get shared and resold repeatedly across Telegram channels. Check If You Are Affected: If you have a topmail.at address, check it now with HEROIC's free breach scanner, which searches more than 400 billion breached records. If your account is listed, change that password immediately, everywhere you've used it.