Digium Asterisk 1.6.0.18

chan_sip.c in the SIP channel driver in Asterisk Open Source 1.6.x before 1.6.2.18.1 and 1.8.x before 1.8.4.3 does not properly handle '\0' characters in SIP packets, which allows remote attackers to cause a denial of service (memory corruption) or possibly have unspecified other impact via a crafted packet.

rtp.c in Asterisk Open Source 1.2.x before 1.2.37, 1.4.x before 1.4.27.1, 1.6.0.x before 1.6.0.19, and 1.6.1.x before 1.6.1.11; Business Edition B.x.x before B.2.5.13, C.2.x.x before C.2.4.6, and C.3.x.x before C.3.2.3; and s800i 1.3.x before 1.3.0.6 allows remote attackers to cause a denial of service (daemon crash) via an RTP comfort noise payload with a long data length.

main/acl.c in Asterisk Open Source 1.6.0.x before 1.6.0.25, 1.6.1.x before 1.6.1.17, and 1.6.2.x before 1.6.2.5 does not properly enforce remote host access controls when CIDR notation "/0" is used in permit= and deny= configuration rules, which causes an improper arithmetic shift and might allow remote attackers to bypass ACL rules and access services from unauthorized hosts.