CVE-2006-5551: Qksoft Qk Smtp

High severity, CVSS 7.5. EPSS: 5.2% chance of exploitation in the next 30 days.

Stack-based buffer overflow in QK SMTP 3.01 and earlier might allow remote attackers to execute arbitrary code via a long argument to the RCPT TO command.

Affected products

• Qksoft Qk Smtp: up to and including 3.0.1

Published 2006-10-26. Last modified 2026-06-16.