Unspecified vulnerability in Asterisk Open Source 1.2.x before 1.2.27, 1.4.x before 1.4.18.1 and 1.4.19-rc3; Business Edition A.x.x, B.x.x before B.2.5.1, and C.x.x before C.1.6.2; AsteriskNOW 1.0.x before 1.0.2; Appliance Developer Kit before 1.4 revision 109393; and s800i 1.0.x before 1.1.0.2; allows remote attackers to access the SIP channel driver via a crafted From header.

Asterisk Open Source 1.2.x before 1.2.26 and 1.4.x before 1.4.16, and Business Edition B.x.x before B.2.3.6 and C.x.x before C.1.0-beta8, when using database-based registrations ("realtime") and host-based authentication, does not check the IP address when the username is correct and there is no password, which allows remote attackers to bypass authentication using a valid username.

Stack-based buffer overflow in the IAX2 channel driver (chan_iax2) in Asterisk before 1.2.22 and 1.4.x before 1.4.8, Business Edition before B.2.2.1, AsteriskNOW before beta7, Appliance Developer Kit before 0.5.0, and s800i before 1.0.2 allows remote attackers to execute arbitrary code by sending a long (1) voice or (2) video RTP frame.

The IAX2 channel driver (chan_iax2) in Asterisk before 1.2.22 and 1.4.x before 1.4.8, Business Edition before B.2.2.1, AsteriskNOW before beta7, Appliance Developer Kit before 0.5.0, and s800i before 1.0.2 allows remote attackers to cause a denial of service (crash) via a crafted (1) LAGRQ or (2) LAGRP frame that contains information elements of IAX frames, which results in a NULL pointer dereference when Asterisk does not properly set an associated variable.

The STUN implementation in Asterisk 1.4.x before 1.4.8, AsteriskNOW before beta7, Appliance Developer Kit before 0.5.0, and s800i before 1.0.2 allows remote attackers to cause a denial of service (crash) via a crafted STUN length attribute in a STUN packet sent on an RTP port.

The Skinny channel driver (chan_skinny) in Asterisk before 1.2.22 and 1.4.x before 1.4.8, Business Edition before B.2.2.1, AsteriskNOW before beta7, Appliance Developer Kit before 0.5.0, and s800i before 1.0.2 allows remote attackers to cause a denial of service (crash) via a certain data length value in a crafted packet, which results in an "overly large memcpy."

The SIP channel driver (chan_sip) in Asterisk before 1.2.18 and 1.4.x before 1.4.3 does not properly parse SIP UDP packets that do not contain a valid response code, which allows remote attackers to cause a denial of service (crash).

The Manager Interface in Asterisk before 1.2.18 and 1.4.x before 1.4.3 allows remote attackers to cause a denial of service (crash) by using MD5 authentication to authenticate a user that does not have a password defined in manager.conf, resulting in a NULL pointer dereference.

The handle_response function in chan_sip.c in Asterisk before 1.2.17 and 1.4.x before 1.4.2 allows remote attackers to cause a denial of service (crash) via a SIP Response code 0 in a SIP packet.

Asterisk 1.4 before 1.4.1 and 1.2 before 1.2.16 allows remote attackers to cause a denial of service (crash) by sending a Session Initiation Protocol (SIP) packet without a URI and SIP-version header, which results in a NULL pointer dereference.