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TI-2020-16483 Aliases CVE-2020-27121GHSA-7c3f-h49g-4mg6

Cisco Unified Communications Manager IM and Presence Service Denial of Service Vulnerability

Priority LOW 31CWE-248Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-248.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01164 67th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
CiscoCisco Unified Communications Manager IM and Presence Serviceall versions—No fix listedCNA
  • Cisco Unified Communications Manager IM and Presence Service VendorCisco Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:cisco:unified_communications_manager_im_and_presence_service:12.5\(1\):*:*:*:*:*:*:*12.5(1)VulnerableCisco
  • cpe:2.3:a:cisco:unified_communications_manager_im_and_presence_service:12.5\(1\):*:*:*:*:*:*:* Versions 12.5(1) Vulnerable ·Cisco

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2020-27121
  2. 2026-10-03 Alias added: GHSA-7c3f-h49g-4mg6

References

Advisory 1

  • TI-2026-16259 Cisco Unified Communications Products Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2021-19919 Apache Log4j2 JNDI features do not protect against attacker controlled LDAP and other JNDI related endpoints KEVCVSS 3.1CRITICAL 10.0
  • TI-2024-13188 Deserialization of untrusted data in Cisco Unified Contact Center Enterprise CVSS 3.1CRITICAL 10.0
  • TI-2019-01468 Improper input validation in Cisco TelePresence Video Communication Server CVSS 3.0HIGH 8.6
  • TI-2017-09109 Improper authentication in Cisco Voice Operating System CVSS 3.0CRITICAL 9.8
  • TI-2018-00368 Improper input validation in Cisco Unified Communications Manager IM & Presence Service CVSS 3.1HIGH 7.5
See all 38 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences