CVE-2006-0021: Microsoft Windows 2003 Server

High severity, CVSS 7.8. EPSS: 62.9% chance of exploitation in the next 30 days.

Microsoft Windows XP SP1 and SP2, and Server 2003 up to SP1, allows remote attackers to cause a denial of service (hang) via an IGMP packet with an invalid IP option, aka the "IGMP v3 DoS Vulnerability."

Affected products

• Microsoft Windows 2003 Server: version datacenter_64-bit only; version enterprise only; version enterprise_64-bit only; version r2 only; version standard only; version standard_64-bit only; …
• Microsoft Windows XP: any version

Published 2006-02-14. Last modified 2026-06-16.