CVE-2019-1721: Cisco Expressway Series and Cisco TelePresence Video Communication Server Denial of Service Vulnerability

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2019-04-18 · updated 2026-06-17
Weakness: CWE-20

Description

A vulnerability in the phone book feature of Cisco Expressway Series and Cisco TelePresence Video Communication Server (VCS) could allow an authenticated, remote attacker to cause the CPU to increase to 100% utilization, causing a denial of service (DoS) condition on an affected system. The vulnerability is due to improper handling of the XML input. An attacker could exploit this vulnerability by sending a Session Initiation Protocol (SIP) message with a crafted XML payload to an affected device. A successful exploit could allow the attacker to exhaust CPU resources, resulting in a DoS condition. Manual intervention may be required to recover the device. This vulnerability is fixed in Cisco Expressway Series and Cisco TelePresence Video Communication Server Releases X12.5.1 and later.

Affected products

Cisco TelePresence Video Communication Server (VCS) Expressway: before x12.5.1 — fixed in x12.5.1

How to fix

Upgrade to a fixed version: Cisco TelePresence Video Communication Server (VCS) Expressway x12.5.1. Check the vendor advisory for mitigations.

References

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