Cisco IOS 12.2 through 12.4 and 15.0 through 15.1, Cisco IOS XE 2.5.x and 2.6.x before 2.6.1, and Cisco Unified Communications Manager (aka CUCM, formerly CallManager) 6.x before 6.1(5)SU1, 7.x before 7.1(5), and 8.0 before 8.0(2) allow remote attackers to cause a denial of service (device reload or voice-services outage) via crafted SIP registration traffic over UDP, aka Bug IDs CSCtf72678 and CSCtf14987.

Unspecified vulnerability in the NAT for SIP implementation in Cisco IOS 12.1 through 12.4 and 15.0 through 15.1 allows remote attackers to cause a denial of service (device reload) via transit traffic on UDP port 5060, aka Bug ID CSCtf17624.

Cisco IOS 12.2 through 12.4 and 15.0 through 15.1, Cisco IOS XE 2.5.x and 2.6.x before 2.6.1, and Cisco Unified Communications Manager (aka CUCM, formerly CallManager) 6.x before 6.1(5), 7.0 before 7.0(2a)su3, 7.1su before 7.1(3b)su2, 7.1 before 7.1(5), and 8.0 before 8.0(1) allow remote attackers to cause a denial of service (device reload or voice-services outage) via a SIP REFER request with an invalid Refer-To header, aka Bug IDs CSCta20040 and CSCta31358.

Unspecified vulnerability in the NAT for H.323 implementation in Cisco IOS 12.1 through 12.4 and 15.0 through 15.1 allows remote attackers to cause a denial of service (device reload) via transit traffic, aka Bug ID CSCtf91428.

Unspecified vulnerability in the NAT for H.225.0 implementation in Cisco IOS 12.1 through 12.4 and 15.0 through 15.1 allows remote attackers to cause a denial of service (device reload) via transit traffic, aka Bug ID CSCtd86472.

Cisco IOS 12.1 through 12.4, and 15.0M before 15.0(1)M1, allows remote attackers to cause a denial of service (interface queue wedge) via malformed H.323 packets, aka Bug ID CSCta19962.

Cisco IOS 12.2 through 12.4, when certain PMTUD, SNAT, or window-size configurations are used, allows remote attackers to cause a denial of service (infinite loop, and device reload or hang) via a TCP segment with crafted options, aka Bug ID CSCsz75186.

Cisco IOS 12.0 through 12.4, when IP-based tunnels and the Cisco Express Forwarding feature are enabled, allows remote attackers to cause a denial of service (device reload) via a malformed packet that is not properly handled during switching from one tunnel to a second tunnel, aka Bug IDs CSCsh97579 and CSCsq31776.

Cisco IOS 12.0 through 12.4, when IP-based tunnels and the Cisco Express Forwarding feature are enabled, allows remote attackers to cause a denial of service (device reload) via malformed packets, aka Bug ID CSCsx70889.

Race condition in the Firewall Authentication Proxy feature in Cisco IOS 12.0 through 12.4 allows remote attackers to bypass authentication, or bypass the consent web page, via a crafted request, aka Bug ID CSCsy15227.