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

BLUF

 Cisco CVE-2026-20045 is a critical code injection vulnerability affecting the web-based management interface of Cisco Unified Communications products. It has been recently reported as being actively exploited in the wild.

Executive Cost Summary

This cost analysis was developed by the CyberDax team using expert judgment and assisted analytical tools to support clarity and consistency.

For organizations affected by exploitation or emergency remediation of CVE-2026-20045 in Cisco Unified Communications environments:

·       Low-end total cost: $250K – $600K

·       (limited exposure, rapid patching, no confirmed persistence or data misuse)

·       Typical expected range: $900K – $2.4M

·       (confirmed compromise of management interface, short operational disruption)

·       Upper-bound realistic scenarios: $4.0M – $8.5M

·       (multi-system impact, regulatory review, prolonged service instability)

Key Cost Drivers

·       Scale and distribution of Cisco Unified Communications deployments

·       Duration between exploit availability and patch application

·       Dependence of revenue operations on voice and collaboration services

·       Need for third-party forensic and incident response support

·       Regulatory exposure tied to recorded or regulated communications

Targeted Sectors

·       Organizations using Cisco Unified Communications solutions, particularly those utilizing web-based management interfaces

Countries

·       Global

Date of First Reported Activity

·       January 21, 2026

Date of Last Reported Activity Update

·       January 21, 2026

CVE-2026-20045

CVSS 3.1

·       (8.2) AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

Nessus ID

·       Not applicable at time of reporting.

Is CVE-2026-20045 in the KEV catalog?

·       Yes

What is the CISA patch by date?

·       February 11, 2026

What is the URL to the patch information for CVE-2026-20045?

·       hxxps://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-voice-rce-mORhqY4b

Affected Products

This vulnerability affects the following Cisco products, regardless of device configuration:

·       Unified CM (CSCwr21851)

·       Unified CM SME (CSCwr21851)

·       Unified CM IM&P (CSCwr29216)

·       Unity Connection (CSCwr29208)

·       Webex Calling Dedicated Instance (CSCwr21851)

Mitigation Data

·       There are no workarounds that address this vulnerability.

Patch Release Date

·       January 21, 2026

URL to patch information

·       hxxps://lists.apache.org/thread/xy51d2fx6drzhfp92xptsx5845q7b37m

APT Names

·       No specific APT group has been publicly linked to CVE-2026-20045

Associated Criminal Organizations

·       No specific criminal organization has been publicly linked to CVE-2026-20045

Malware Names

·       No malware has been specifically associated to CVE-2026-20045 at this time.

Malware Sample

·       Not applicable at this time

Tools Used by Attackers

·       Custom exploit scripts targeting the /pprof/heap endpoint.

Likely IOCs

Observed Network IOCs

·       Target Ports Exploitation attempts primarily target TCP port 443 (HTTPS) and TCP port 8443, which are used by Cisco administration interfaces.

·       Abnormal User-Agent Strings

o   Automated exploitation tools often use non-standard or older browser User-Agent strings. Look for headers such as User-Agent: python-requests/2.x.x or User-Agent: curl/7.x.x directed at administrative URI paths.

·       Unusual URI Paths

o   Inbound requests to paths like /voice/admin/, /ucm/config/, or specialized API endpoints that result in HTTP 200 responses from internal assets should be scrutinized.

Host-Based Indicators

·       Unauthorized Configuration Changes: Check for the creation of new administrative accounts or unexpected modifications to dial plans and system settings within the Cisco Unified Communications Manager.

·       Abnormal Process Activity: Look for child processes spawned by web server services (e.g., tomcat or apache) that execute shell commands or system utilities like whoami, ifconfig, or netstat.

·       System Log Anomalies: Monitor for logs indicating failed login attempts followed by a single successful administrative login from an unfamiliar IP address, specifically targeting the management interface.

TTPs

·       T1190 Exploit Public-Facing Application

o   Adversaries target the vulnerable Cisco Unified Communications application exposed to the network to gain initial access.

·       T1059 Command and Scripting Interpreter

o   Once injected, the malicious code typically utilizes system shells or scripting interpreters (such as Bash or Python) to execute further commands on the host.

·       T1068 Exploitation for Privilege Escalation

o   Attackers may leverage the code injection to execute commands with the privileges of the Cisco application service, potentially leading to full system compromise.

·       T1565 Data Manipulation

o   Given the nature of Unified Communications, this vulnerability may be used to intercept or manipulate communication data.

Suggested rules / potential hunts

As a reminder, these are indicator rules. They are likely to be noisy.

For best results consider creating a data model and reviewing the traffic as a report.

Suricata

Monitors for common shell commands or unexpected binary execution strings within HTTP POST bodies directed at Unified CM or Unity Connection endpoints

bash

alert http $EXTERNAL_NET any -> $HOME_NET [80,443] (msg:"ET EXPLOIT Cisco Unified Communications Manager Code Injection Attempt (CVE-2026-20045)"; flow:established,to_server; content:"POST"; http_method; pcre:"/(?:bin\/sh|powershell|cmd\.exe)/Pi"; reference:cve,2026-20045; classtype:attempted-admin; sid:10002026; rev:1;)

SentinelOne

Suspicious Child Processes of Web Services

sql

Process.Parent.Name in ("tomcat", "httpd", "nginx", "java")

AND Process.Name in ("sh", "bash", "python", "perl", "nc", "netcat")

Privileged Escalation Monitoring

sql

Process.Name in ("chmod", "chown", "sudo", "su")

AND Process.Parent.Name in ("sh", "bash")

AND Process.CmdLine contains any ("+x", "777", "root")

Detection of outbound network connections initiated by the web application processes to non-standard ports or known malicious IPs.

sql

Process.Parent.Name in ("tomcat", "java")

AND (Network.Direction = "Outbound" AND Network.Port not in (80, 443, 53))

Search for the creation of new scripts or executable files within common Cisco Unified Communications web directories (e.g., /usr/local/webstack/, /opt/cisco/).

sql

File.Action = "Create"

AND File.Path contains any ("/webapps/", "/html/", "/scripts/")

AND File.Extension in ("jsp", "php", "sh", "py")

Splunk

Hunt for Shell Activity (Splunk Search):

spl

index=cisco_logs sourcetype=syslog ("bin/sh" OR "bash")

| stats count by host, user, process_name, command_line

Hunt for Unexpected Root Escalation

spl

index=os_logs (sourcetype=linux_secure OR sourcetype=syslog) "sudo" OR "su -"

| search NOT [| inputlookup known_admin_activities.csv]

| table _time, host, user, command

Delivery Method

·       Typically involves sending a specially crafted, malicious HTTP request to the vulnerable web interface of the appliance

Email sample

·       Not applicable at this time

References

SEC CloudApps Cisco

·       hxxps://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-voice-rce-mORhqY4b

NVD

·       hxxps://nvd.nist.gov/vuln/detail/CVE-2026-20045

CISA KEV catalog

·       hxxps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20045