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.

Memory leak in the H.323 implementation in Cisco IOS 12.1 through 12.4, and 15.0M before 15.0(1)M1, allows remote attackers to cause a denial of service (memory consumption and device reload) via malformed H.323 packets, aka Bug ID CSCtb93855.

Cisco IOS 12.1 through 12.4, when Cisco Unified Communications Manager Express (CME) or Cisco Unified Survivable Remote Site Telephony (SRST) is enabled, allows remote attackers to cause a denial of service (device reload) via a malformed Skinny Client Control Protocol (SCCP) message, aka Bug ID CSCsz48614, the "SCCP Packet Processing Denial of Service Vulnerability."

Unspecified vulnerability in Cisco IOS 12.0 through 12.4, IOS XE 2.1.x through 2.3.x before 2.3.2, and IOS XR 3.2.x through 3.4.3, when Multiprotocol Label Switching (MPLS) and Label Distribution Protocol (LDP) are enabled, allows remote attackers to cause a denial of service (device reload or process restart) via a crafted LDP packet, aka Bug IDs CSCsz45567 and CSCsj25893.

Cisco IOS 12.1 through 12.4, when Cisco Unified Communications Manager Express (CME) or Cisco Unified Survivable Remote Site Telephony (SRST) is enabled, allows remote attackers to cause a denial of service (device reload) via a malformed Skinny Client Control Protocol (SCCP) message, aka Bug ID CSCsz49741, the "SCCP Request Handling Denial of Service Vulnerability."

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.

The (1) Cisco Unified Communications Manager Express; (2) SIP Gateway Signaling Support Over Transport Layer Security (TLS) Transport; (3) Secure Signaling and Media Encryption; (4) Blocks Extensible Exchange Protocol (BEEP); (5) Network Admission Control HTTP Authentication Proxy; (6) Per-user URL Redirect for EAPoUDP, Dot1x, and MAC Authentication Bypass; (7) Distributed Director with HTTP Redirects; and (8) TCP DNS features in Cisco IOS 12.0 through 12.4 do not properly handle IP sockets, which allows remote attackers to cause a denial of service (outage or resource consumption) via a series of crafted TCP packets.

Unspecified vulnerability in Cisco IOS 12.0 through 12.4, when SIP voice services are enabled, allows remote attackers to cause a denial of service (device crash) via a valid SIP message.