CVE-2026-20045 — A vulnerability in Cisco Unified Communications Manager (Unified CM), Cisco Unified…¶

Key facts

CVE-2026-20045 is a High (8.2) vulnerability: A vulnerability in Cisco Unified Communications Manager (Unified CM), Cisco Unified…. This entry ships a detection-only PoC and a Docker test lab. It is on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2026-01-21), confirming active exploitation in the wild.

Actively exploited — on the CISA KEV catalog

CVE-2026-20045 is listed on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2026-01-21), confirming exploitation in the wild. Federal remediation deadline: 2026-02-11. Prioritise patching and deploy the detection and prevention rules below.


CVE	CVE-2026-20045
Severity	High (8.2)
CISA KEV	Actively exploited (added 2026-01-21)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-20045/

Details¶

English | 한국어

Description¶

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.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-20045
Type	RCE
CVSS Score	8.2

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-20045/poc.py

Usage¶

# Run PoC against target
python3 poc.py --target <TARGET_URL>

# With authentication
python3 poc.py --target <TARGET_URL> --username <USER> --password <PASS>

⚠️ Warning: This PoC is for authorized security testing only. It uses detection-only techniques and does not exploit or damage target systems.

Test Lab¶

This repository includes a Docker-based test environment with both vulnerable and patched applications.

Quick Start¶

# Clone and navigate to CVE directory
cd CVE-2026-20045

# Start both applications
docker-compose up -d

# Run tests
./run-tests.sh    # Linux/Mac
./run-tests.ps1   # Windows PowerShell

Application Endpoints¶

Application	URL	Status
Vulnerable App	http://localhost:8080	Shows vulnerability
Patched App	http://localhost:8081	Demonstrates fix

Directory Structure¶

├── README.md           # English documentation
├── README_KO.md        # Korean documentation
├── poc.py              # PoC detection script
├── docker-compose.yml  # Container orchestration
├── run-tests.sh        # Linux/Mac test runner
├── run-tests.ps1       # Windows test runner
├── vulnerable-app/     # Vulnerable version
│   ├── app.py
│   ├── Dockerfile
│   └── requirements.txt
└── patched-app/        # Fixed version
    ├── app.py
    ├── Dockerfile
    └── requirements.txt

References¶

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-voice-rce-mORhqY4b
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20045

Generated by PoC Generator on 2026-01-25T14:49:21.446298129

Frequently asked questions¶

What is CVE-2026-20045?¶

CVE-2026-20045 is a High (8.2) vulnerability: A vulnerability in Cisco Unified Communications Manager (Unified CM), Cisco Unified…. This entry ships a detection-only PoC and a Docker test lab. It is on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2026-01-21), confirming active exploitation in the wild.

How do I detect CVE-2026-20045?¶

Run the detection-only PoC included with this entry against your Docker test lab to confirm whether a target is affected; pair it with your own IDS logging.

How do I block or mitigate CVE-2026-20045?¶

Upgrade to a fixed version per the vendor advisory; the NVD record lists the affected versions. Use the included PoC to verify your remediation.

Is CVE-2026-20045 actively exploited?¶

Yes. CVE-2026-20045 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, added 2026-01-21, which means it has been exploited in the wild. CISA set a federal remediation deadline of 2026-02-11. Prioritise patching and deploy the detection and prevention rules above.

For authorized security testing and research only. See the full source and NVD record.