CVE-2026-20150

Executive Summary

CVE-2026-20150 is a high-severity vulnerability (CVSS 8.8) affecting Cisco RoomOS, the operating system for Cisco collaboration devices such as video conferencing endpoints and room systems. The vulnerability stems from improper access control (CWE-284), allowing an unauthenticated, remote attacker to potentially gain unauthorized access to sensitive system functions or data. The vulnerability was discovered during an internal security review by Cisco’s RoomOS engineering team and has been addressed through a software hardening release. No public exploit code or proof-of-concept is currently available, and the EPSS score is 0.0%, indicating a low likelihood of exploitation in the wild at this time. However, given the critical nature of the affected devices in enterprise environments, immediate patching is strongly recommended.

CVSS Breakdown & Threat Level

• CVSS Score: 8.8 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
• Attack Vector: Network (AV:N) – The vulnerability can be exploited remotely over the network.
• Attack Complexity: Low (AC:L) – No special conditions or complex attack sequences are required.
• Privileges Required: None (PR:N) – No authentication is needed to exploit the vulnerability.
• User Interaction: None (UI:N) – No user action is required for exploitation.
• Scope: Unchanged (S:U) – The vulnerability does not affect resources beyond the vulnerable component.
• Confidentiality Impact: High (C:H) – An attacker could gain access to sensitive information.
• Integrity Impact: High (I:H) – An attacker could modify system data or configurations.
• Availability Impact: High (A:H) – An attacker could disrupt system availability.

Threat Level: High. The vulnerability is remotely exploitable with low complexity and no authentication, making it a prime target for attackers. Although no public exploits exist yet, the potential for widespread impact in enterprise environments is significant.

Deep Dive & Mechanics

CVE-2026-20150 is rooted in improper access control within Cisco RoomOS. The vulnerability likely resides in the web management interface or API endpoints that handle device configuration, user management, or media stream control. Due to insufficient authorization checks, an unauthenticated attacker can send crafted HTTP requests to the device, bypassing authentication mechanisms and gaining access to privileged functions.

The attack surface includes:

• Web Management Interface: Typically exposed on TCP port 443 (HTTPS) or 80 (HTTP).
• API Endpoints: RESTful APIs used for device provisioning, status monitoring, and remote management.
• Media Control Protocols: Potentially exploitable via SIP or H.323 signaling.

An attacker could exploit this vulnerability to:

• Retrieve sensitive configuration data (e.g., network credentials, SIP passwords).
• Modify device settings (e.g., redirect media streams, disable security features).
• Cause denial of service by crashing critical services.

The internal nature of the discovery suggests the vulnerability is not trivial to find but is straightforward to exploit once identified.

Vulnerable vs. Patched Code

Since no specific code snippets are publicly available, the following is a hypothetical example illustrating the vulnerability:

Vulnerable Code (Python/Flask example):

@app.route('/api/device/config', methods=['GET'])
def get_device_config():
    # No authentication check
    config = load_config()
    return jsonify(config)

Patched Code:

@app.route('/api/device/config', methods=['GET'])
@require_authentication
def get_device_config():
    config = load_config()
    return jsonify(config)

The patched version adds an authentication decorator (@require_authentication) that validates the user’s session or API token before allowing access to sensitive endpoints.

Exploitation & Lab Setup

Red Team

Objective: Gain unauthorized access to a Cisco RoomOS device and extract sensitive configuration data.

Prerequisites:

• A vulnerable Cisco RoomOS device (e.g., Webex Room Kit, Room 55, Room 70).
• Network access to the device’s management interface (e.g., IP address on the same subnet).

Steps:

1. Reconnaissance: Scan the target device for open ports (e.g., 80, 443, 5060 for SIP).

   nmap -sV -p 80,443,5060 <target_ip>
   

2. Identify Vulnerable Endpoint: Use a web fuzzer to discover API endpoints.

   ffuf -u https://<target_ip>/api/FUZZ -w /usr/share/wordlists/api_endpoints.txt
   

3. Exploit: Send a crafted request to an unprotected endpoint.

   curl -k https://<target_ip>/api/device/config
   

4. Extract Data: Parse the response for sensitive information (e.g., SIP passwords, network credentials).

Expected Outcome: The attacker retrieves the device configuration without authentication.

Blue Team

Objective: Detect and block exploitation attempts against Cisco RoomOS devices.

Detection Strategy:

• Monitor for unusual HTTP requests to API endpoints without authentication headers.
• Alert on multiple failed login attempts or requests to sensitive endpoints from unknown IPs.
• Use network segmentation to limit access to management interfaces.

Lab Setup:

• Deploy a Cisco RoomOS device in a isolated VLAN.
• Use a SIEM (e.g., Splunk, ELK) to collect logs from the device.
• Simulate exploitation using the Red Team steps above and verify detection rules.

Indicators of Compromise (IOCs)

• Network IOCs:
  • Unusual HTTP requests to /api/device/config, /api/admin, or similar endpoints.
  • Requests from IP addresses not in the allowed management subnet.
  • Multiple requests to different API endpoints in a short time (fuzzing behavior).
• Host IOCs:
  • Unauthorized changes to device configuration (e.g., new SIP accounts, modified network settings).
  • Unexpected reboots or service crashes.
  • Log entries showing access to restricted endpoints without authentication.
• File IOCs:
  • Modified configuration files (e.g., config.xml, settings.json).
  • Presence of unauthorized scripts or binaries in the device filesystem.

Detection Engineering

YARA Rule

rule cve_2026_20150_roomos_access_control {
    meta:
        description = "Detects exploitation attempts for CVE-2026-20150 in Cisco RoomOS"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2026-20150"
    strings:
        $s1 = "/api/device/config" ascii wide nocase
        $s2 = "/api/admin" ascii wide nocase
        $s3 = "GET /api/" ascii wide nocase
    condition:
        any of ($s*) and #s3 > 5
}

Sigma Rule

title: CVE-2026-20150 - Unauthenticated Access to Cisco RoomOS API
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects HTTP requests to sensitive Cisco RoomOS API endpoints without authentication
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: cisco_roomos
detection:
    selection:
        cs-method: 'GET'
        cs-uri-stem:
            - '/api/device/config'
            - '/api/admin'
            - '/api/system'
    condition: selection
falsepositives:
    - Legitimate administrative access from trusted IPs
level: high

Suricata Rule

alert http any any -> $HOME_NET any (
    msg:"CVE-2026-20150 - Unauthenticated Access to Cisco RoomOS API";
    flow:to_server,established;
    content:"GET"; http_method;
    content:"/api/"; http_uri;
    pcre:"/\/api\/(device\/config|admin|system)/Ui";
    classtype:attempted-admin;
    sid:1000001;
    rev:1;
    reference:cve,2026-20150;
)

Remediation & Mitigation

Immediate Actions:

1. Apply the Software Hardening Release: Cisco has released a software update that addresses this vulnerability. Update all affected RoomOS devices to the latest version.
2. Restrict Network Access: Limit access to the device management interface to trusted IP addresses only using firewall rules or ACLs.
3. Disable Unnecessary Services: If the web interface is not required, disable it or restrict it to local access only.

Long-Term Mitigations:

• Network Segmentation: Place RoomOS devices in a dedicated VLAN with strict access controls.
• Monitoring: Implement logging and monitoring for all administrative access to RoomOS devices.
• Regular Audits: Conduct periodic security reviews of device configurations and access logs.
• Vendor Communication: Subscribe to Cisco security advisories for future updates.

Workarounds (if patching is not immediately possible):

• Use a reverse proxy with authentication (e.g., Apache, Nginx) in front of the device.
• Implement IP whitelisting on the device itself (if supported).

Valters IT
Securing Your Digital Frontier