The Vuln_SMTP Leak: 3,254 SMTP Logins Quietly Surfaced

HEROIC analysts found a combolist called Vuln_SMTP uploaded to a Telegram channel on July 4, 2026. The file contains 3,254 records of email addresses, plaintext passwords, and URLs pointing to SMTP mail servers. Why This Is Dangerous: SMTP credentials control the ability to send email through a mail server. In the wrong hands, a working login can be used to send spam or phishing emails that appear to come from a legitimate address, damaging the reputation of that email domain and tricking other people into trusting messages that are not really from the account owner. What Was Exposed: - Email addresses - Plaintext passwords - SMTP server login URLs Why This Matters: This leak did not make headlines and likely never will, but 3,254 real email and password combinations are now circulating quietly among people who know how to use them. Beyond abusing the mail servers directly, attackers often test these same credentials against other websites, since so many people reuse passwords. That opens the door to account takeover and identity theft well beyond the original email account. How a Combolist Like This Works: This type of combolist is typically built by scanning for exposed or poorly secured mail servers and harvesting the login credentials attackers find, then compiling them into a plain text file. These lists are shared on Telegram specifically because SMTP access is valuable for running spam and phishing campaigns at scale. Check If You Are Affected: Quiet leaks like this one are easy to miss, which is exactly why they are dangerous. HEROIC's free breach scanner checks your email against more than 400 billion leaked records, so you can see if your information is part of this file or any other before it's used against you.