CVE-2020-27121: Cisco Unified Communications Manager Im And Presence Service

Medium severity, CVSS 6.5. EPSS: 1.2% chance of exploitation in the next 30 days.

A vulnerability in Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&P) Software could allow an authenticated, remote attacker to cause the Cisco XCP Authentication Service on an affected device to restart, resulting in a denial of service (DoS) condition. The vulnerability is due to improper handling of login requests. An attacker could exploit this vulnerability by sending a crafted client login request to an affected device. A successful exploit could allow the attacker to cause a process to crash, resulting in a DoS condition for new login attempts. Users who are authenticated at the time of the attack would not be affected. There are workarounds that address this vulnerability.

Affected products

• Cisco Unified Communications Manager Im And Presence Service: version 12.5(1) only

Published 2020-11-06. Last modified 2026-06-17.