CVE-2023-20259: Cisco Emergency Responder

High severity, CVSS 7.5. EPSS: 0.8% chance of exploitation in the next 30 days.

A vulnerability in an API endpoint of multiple Cisco Unified Communications Products could allow an unauthenticated, remote attacker to cause high CPU utilization, which could impact access to the web-based management interface and cause delays with call processing. This API is not used for device management and is unlikely to be used in normal operations of the device. This vulnerability is due to improper API authentication and incomplete validation of the API request. An attacker could exploit this vulnerability by sending a crafted HTTP request to a specific API on the device. A successful exploit could allow the attacker to cause a denial of service (DoS) condition due to high CPU utilization, which could negatively impact user traffic and management access. When the attack stops, the device will recover without manual intervention.

Affected products

• Cisco Emergency Responder: version 14su3 only
• Cisco Prime Collaboration Deployment: version 14su3 only
• Cisco Unified Communications Manager: version 12.5(1)su7 only; version 14su3 only
• Cisco Unified Communications Manager Im & Presence Service: version 12.5(1)su7 only; version 14su3 only
• Cisco Unity Connection: version 14su3 only

Published 2023-10-04. Last modified 2026-06-17.