Buffer overflow in the Multimedia PC Client in Nortel Multimedia Communication Server (MCS) before Maintenance Release 3.5.8.3 and 4.0.25.3 allows remote attackers to cause a denial of service (crash) via a flood of "extraneous" messages, as demonstrated by the Nessus "Generic flood" denial of service plugin.

Buffer overflow in the Nortel UNIStim IP Softphone 2050 allows remote attackers to cause a denial of service (application abort) and possibly execute arbitrary code via a flood of invalid characters to the RTCP port (5678/udp) that triggers a Windows error message, aka "extraneous messaging."

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.

The Nortel UNIStim IP Softphone 2050, IP Phone 1140E, and other Nortel IP Phone, Mobile Voice Client, and WLAN Handsets products allow remote attackers to cause a denial of service (device hang) via a flood of Mute and UnMute messages that have a spoofed source IP address for the Signaling Server.

The Nortel UNIStim IP Softphone 2050, IP Phone 1140E, and additional Nortel products from the IP Phone, Business Communications Manager (BCM), and other product lines, use only 65536 different values in the 32-bit ID number field of an RUDP datagram, which makes it easier for remote attackers to guess the RUDP ID and spoof messages. NOTE: this can be leveraged for an eavesdropping attack by sending many Open Audio Stream messages.

The Nortel UNIStim IP Softphone 2050, IP Phone 1140E, and additional Nortel products from the IP Phone, Business Communications Manager (BCM), and other product lines allow remote attackers to eavesdrop on the physical environment via an Open Audio Stream message that enables "surveillance mode." NOTE: issues relating to a small ID number space can be leveraged to make this attack easier.

The CS1000 signaling server in Nortel Enterprise VoIP-Core-CS 1000M Chassis/Cabinet, Enterprise VoIP-Core-CS 1000E and 1000S, Meridian-Core-Option 11C Chassis and Cabinet, and Meridian-Core-Option 51C, 61C, and 81C allows remote attackers to cause a denial of service (telephony application outage) via a flood of packets to Embedded LAN (ELAN) ports.

Buffer overflow in the SIP header parsing module in the Nortel PC Client SIP Soft Phone 4.1 3.5.208[20051015] allows remote attackers to execute arbitrary code via a malformed message, a different vulnerability than CVE-2007-3361.

The Nortel PC Client SIP Soft Phone 4.1 3.5.208[20051015] allows remote attackers to cause a denial of service (device crash) via a SIP message with a malformed header.

Unspecified vulnerability in the Nortel CS 1000 M media card in Enterprise VoIP-Core-CS 1000E, 1000M, and 1000S 04.50W before 20070523 in Meridian/CS 1000 allows remote attackers to cause a denial of service (card hang) via unspecified vectors.