CVE-2007-5640: Nortel Business Communications Manager

High severity, CVSS 7.1. EPSS: 1.8% chance of exploitation in the next 30 days.

The Nortel UNIStim IP Softphone 2050, IP Phone 1140E, and additional Nortel products from the IP Phone, Business Communications Manager (BCM), Mobile Voice Client, and other product lines, allow remote attackers to block calls and force re-registration via a resume message to the Signaling Server that has a spoofed source IP address for the phone. NOTE: the attack is more disruptive if a new spoofed resume message is sent after each re-registration.

Affected products

• Nortel Business Communications Manager: version 50 only; version 50a only; version 50e only; version 200 only; version 400 only; version 1000 only; …
• Nortel Centrex IP Client Manager: any version
• Nortel Centrex IP Element Manager: any version
• Nortel Meridian Option 11c: any version
• Nortel Meridian Option 51c: any version
• Nortel Meridian Option 61c: any version
• Nortel Meridian Option 81c: any version
• Nortel Meridian SL100: version cs2100 only
• Nortel Mobile Voice Client 2050: any version

Published 2007-10-23. Last modified 2026-06-16.