CVE-2026-20045: Cisco Unified Communications Products Code Injection Vulnerability

In short

Cisco Unified Communications Manager has a weakness classified as code injection (CWE-94). CISA added it to its Known Exploited Vulnerabilities catalog on 2026-01-21. NVD lists CVSS 3.1 at 9.8 CRITICAL.

What it is

“Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager Session Management Edition (Unified CM SME), Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&P), Cisco Unity Connection, and Cisco Webex Calling Dedicated Instance contain a code injection vulnerability that could allow the attacker to obtain user-level access to the underlying operating system and then elevate privileges to root.” — CISA KEV, retrieved 2026-11-01

“A vulnerability in Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager Session Management Edition (Unified CM SME), Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&P), Cisco Unity Connection, and Cisco Webex Calling Dedicated Instance could allow an unauthenticated, remote attacker to execute arbitrary commands on the underlying operating system of an affected device.  This vulnerability is due to improper validation of user-supplied input in HTTP requests. An attacker could exploit this vulnerability by sending a sequence of crafted HTTP requests to the web-based management interface of an affected device. A successful exploit could allow the attacker to obtain user-level access to the underlying operating system and then elevate privileges to root.  Note: Cisco has assigned this security advisory a Security Impact Rating (SIR) of Critical rather than High as the score indicates. The reason is that exploitation of this vulnerability could result in an attacker elevating privileges to root.” — NVD, retrieved 2026-11-01

Who is affected

Cisco Unified Communications Manager. NVD lists the following versions as affected:

• Cisco Unified Communications Manager: from 12.5 inclusive, before 14su5
• Cisco Unified Communications Manager: from 15.0 inclusive, through 15su3a
• Cisco Unified Communications Manager Im And Presence Service: from 12.5 inclusive, before 14su5
• Cisco Unified Communications Manager Im And Presence Service: from 15.0 inclusive, through 15su3a
• Cisco Unity Connection: from 12.5 inclusive, before 14su5
• Cisco Unity Connection: from 15.0 inclusive, through 15su3

Exploitation status

CISA KEV added: 2026-01-21. Known ransomware campaign use: Not reported by CISA. Due date CISA set for US federal civilian agencies: 2026-02-11.

Scores

NVD CVSS 3.1: 9.8 CRITICAL; vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H; source [email protected].

EPSS by FIRST: 4.54%; percentile 91.57; score date 2026-10-31. EPSS estimates the probability of exploitation in the next 30 days.

CWE: CWE-94.

Timeline

CISA required action

“Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.” — CISA KEV

What to do

• Confirm whether you run Cisco Unified Communications Manager and which version.
• Apply the vendor update or mitigation in the advisory.
• Follow CISA’s required action.
• Review the vendor guidance on signs of compromise.
• Track the fix through completion.

References

• Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-voice-rce-mORhqY4b
• NVD detail
• CVE.org record
• CISA KEV catalog

Sources and dates

CISA Known Exploited Vulnerabilities Catalog, version 2026.10.30; retrieved 2026-11-01. CISA KEV data: CC0 1.0. No endorsement by CISA.

NVD retrieved: 2026-11-01. This product uses the NVD API but is not endorsed or certified by the NVD.

EPSS scores by FIRST; score date 2026-10-31.