The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

A vulnerability in the authentication service of the Cisco Unified Communications Manager IM and Presence (Unified CM IM&P) Service, Cisco TelePresence Video Communication Server (VCS), and Cisco Expressway Series could allow an unauthenticated, remote attacker to cause a service outage for users attempting to authenticate, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient controls for specific memory operations. An attacker could exploit this vulnerability by sending a malformed Extensible Messaging and Presence Protocol (XMPP) authentication request to an affected system. A successful exploit could allow the attacker to cause an unexpected restart of the authentication service, preventing users from successfully authenticating. Exploitation of this vulnerability does not impact users who were authenticated prior to an attack.

A vulnerability in the XCP Router service of the Cisco Unified Communications Manager IM & Presence Service (CUCM IM&P) and the Cisco TelePresence Video Communication Server (VCS) and Expressway could allow an unauthenticated, remote attacker to cause a temporary service outage for all IM&P users, resulting in a denial of service (DoS) condition. The vulnerability is due to improper validation of user-supplied input. An attacker could exploit this vulnerability by sending a malicious IPv4 or IPv6 packet to an affected device on TCP port 7400. An exploit could allow the attacker to overread a buffer, resulting in a crash and restart of the XCP Router service. Cisco Bug IDs: CSCvg97663, CSCvi55947.

Linux kernel versions 4.9+ can be forced to make very expensive calls to tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() for every incoming packet which can lead to a denial of service.

The IP implementation on Cisco TelePresence Multipoint Switch before 1.8.1, Cisco TelePresence Manager before 1.9.0, and Cisco TelePresence Recording Server 1.8 and earlier allows remote attackers to cause a denial of service (networking outage or process crash) via (1) malformed IP packets, (2) a high rate of TCP connection requests, or (3) a high rate of TCP connection terminations, aka Bug IDs CSCti21830, CSCti21851, CSCtj19100, CSCtj19086, CSCtj19078, CSCty11219, CSCty11299, CSCty11323, and CSCty11338.

The Cisco Discovery Protocol (CDP) implementation on Cisco TelePresence Multipoint Switch before 1.9.0, Cisco TelePresence Immersive Endpoint Devices before 1.9.1, Cisco TelePresence Manager before 1.9.0, and Cisco TelePresence Recording Server before 1.8.1 allows remote attackers to execute arbitrary code by leveraging certain adjacency and sending a malformed CDP packet, aka Bug IDs CSCtz40953, CSCtz40947, CSCtz40965, and CSCtz40953.

Cisco TelePresence Manager 1.2.x through 1.6.x allows remote attackers to bypass authentication and invoke arbitrary methods via a malformed SOAP request, aka Bug ID CSCtc59562.

Cisco TelePresence Manager 1.2.x through 1.6.x allows remote attackers to perform unspecified actions and consequently execute arbitrary code via a crafted request to the Java RMI interface, related to a "command injection vulnerability," aka Bug ID CSCtf97085.

Buffer overflow on Cisco Adaptive Security Appliances (ASA) 5500 series devices with software 1.6.x; Cisco TelePresence Multipoint Switch (CTMS) devices with software 1.0.x, 1.1.x, 1.5.x, and 1.6.x; Cisco TelePresence endpoint devices with software 1.2.x through 1.6.x; and Cisco TelePresence Manager 1.2.x, 1.3.x, 1.4.x, 1.5.x, and 1.6.2 allows remote attackers to execute arbitrary code via a crafted Cisco Discovery Protocol packet, aka Bug IDs CSCtd75769, CSCtd75766, CSCtd75754, and CSCtd75761.

Multiple buffer overflows in the authentication functionality in the web-server module in Cisco CiscoWorks Common Services before 4.0 allow remote attackers to execute arbitrary code via a session on TCP port (1) 443 or (2) 1741, aka Bug ID CSCti41352.