The pro.onet.pl Leak Exposed 1,523 Polish Email Accounts Online

HEROIC analysts identified a combolist tied to the pro.onet.pl domain, dated June 10, 2026, circulating in a Telegram channel. The file contains 1,523 records of email addresses, plaintext passwords, and the URLs the credentials unlock. Why This Leak Is Dangerous: Every password in this file is stored in plain text, meaning an attacker can read and use each one directly without cracking it first. Because the addresses share the pro.onet.pl domain, this list gives criminals a focused set of targets tied to one email provider. What Was Exposed: - Email addresses - Plaintext passwords - URLs linking each account to the pro.onet.pl service Why This Matters: Onet is a widely used email and portal service in Poland, and a compromised account there can be used to reset passwords on other accounts linked to that same email address. Anyone in this list who reused their pro.onet.pl password on another site faces a higher risk of account takeover. How a Domain-Targeted Combolist Like This Works: Attackers filter large batches of stolen credentials down to a single email domain, in this case pro.onet.pl, to create a focused list they can sell to buyers specifically interested in targeting that provider's users, then share it through Telegram groups. Check If You Are Affected: Search your email in HEROIC's free breach scanner, which checks against more than 400 billion leaked records, to see if your pro.onet.pl account was part of this leak, and change your password right away if it was.