A recently discovered security vulnerability, assigned CVE-2025-20156, has been found in the REST API of Cisco Meeting Management. If exploited, this vulnerability could allow a remote, authenticated attacker with low-level privileges to elevate their privileges to an administrator level on an affected device.

The vulnerability was found in the way the REST API of Cisco Meeting Management enforces proper authorization for users. An attacker could exploit this vulnerability by sending API requests to a specific endpoint, allowing them to gain administrator-level control over edge nodes managed by Cisco Meeting Management.

In this post, we'll explore the vulnerability itself in more depth, provide some code snippets to demonstrate the issue, and include links for further reading and remediation. If your organization uses Cisco Meeting Management, it's essential to understand this vulnerability and apply any necessary security updates.

Exploring the Vulnerability

This vulnerability exists due to a lack of proper authorization enforcement for REST API users. An attacker who has successfully authenticated with low privileges can exploit this weakness in authorization by sending a specially crafted API request to a specific endpoint.

The attacker must already have access to the system as an authenticated user to exploit this vulnerability, which can be accomplished through various means such as phishing or social engineering.

To better understand, consider the following code snippet as an example of a malicious API request

POST /api/v1/users/escalate HTTP/1.1
Host: vulnerable.example.com
Authorization: Bearer 123456789abcdefghijklmnop
Content-Type: application/json
{
  "targetUserId": "fill_with_victim_user_id_here"
}

In this example, the attacker sends a POST request to the /api/v1/users/escalate endpoint, which, due to the vulnerability in authorization enforcement, allows the attacker to elevate the target user's privileges to administrator level.

Cisco has officially released a security advisory detailing CVE-2025-20156 and recommended a security update to mitigate the vulnerability. You can read more about this vulnerability and the steps to remediate it in Cisco's official security advisory:

- Cisco Security Advisory: CVE-2025-20156 (link to Cisco's official advisory)

In addition to the official security advisory from Cisco, the following third-party resources provide further information on this vulnerability:

- NVD - CVE-2025-20156
- MITRE - CVE-2025-20156

Conclusion

CVE-2025-20156 is a critical vulnerability in Cisco Meeting Management, which, if exploited, could allow an authenticated attacker with low privileges to escalate their access level to administrator on an affected device. As this vulnerability poses a significant risk to organizations using Cisco Meeting Management, it's crucial to understand the potential impact and apply the necessary security updates as recommended by Cisco.

Stay informed and monitor announcements from security researchers and Cisco. Always practice good cyber hygiene, ensure your organization follows security best practices, and maintain robust and up-to-date access control policies to help protect your organization from vulnerabilities like CVE-2025-20156.

Timeline

Published on: 01/22/2025 17:15:12 UTC
Last modified on: 01/29/2025 16:15:43 UTC