Yealink YMCS RPS Brute-Force Enumeration Vulnerability in SN Verification

A vulnerability exists in Yealink YMCS RPS prior to 2025-06-04, allowing brute-force enumeration of the last five digits of the device serial number. This issue arises from a lack of limits on verification attempts, enabling repeated guesses to successfully enumerate serial numbers.

Impact

Exploitation of this vulnerability allows for brute-force enumeration of the last five digits of the device serial number, potentially leading to unauthorized identification of devices.

Remediation

Yealink has released a security update on June 4, 2025, which has been automatically deployed to all YMCS cloud service instances. For additional information, customers can contact Yealink technical support.