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UK Cyber Defence
VulnerabilityModified

CVE-2020-27121

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…

MEDIUM 6.5EPSS 1.16%

Does this matter?

Lower severity and a low EPSS score (1.16%). Track it; it rarely justifies an emergency change on its own.

Description

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.

CVSS 3.1
6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS
1.16% probability · 67th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-248, CWE-755
Affected
cisco/unified communications manager im and presence service
Source
psirt@cisco.com
EPSS trend
0%3%5%26 October 2026: 1.16%26 October 202626 October 2026

EPSS 1.2% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.