It indicates a possible exploit of Address spoof vulnerability in Microsoft Outlook.
Microsoft Outlook is an email client application that provides an integrated solution for managing and organizing e-mail messages, schedules, tasks, notes, contacts, and other information. An address spoof vulnerability is reported in it that may allow an attacker to spoof "from address" and carry out social engineer and phishing attacks. This is due to Microsoft Outlook and Outlook Web Access (OWA) failure to display properly "From" field in an email message when the "From" field contains multiple comma-separated addresses. This issue may allow an attacker to carry out other attacks by combining with social engineering and phishing attacks. An attacker may also bypass email gateways and send email to users.
Microsoft Outlook 2003 and Microsoft Outlook Web Access 2003.
Apply appropriate patch from the vendor if available.