CVE-2025-28172 affects Grandstream Networks UCM6510 firmware versions 1.0.20.52 and earlier. The vulnerability is due to improper restriction of excessive authentication attempts, allowing attackers to perform an unlimited number of login attempts without lockout or throttling. This weakness can be exploited to brute force user credentials and gain unauthorized access to accounts on the affected device. The CVSS 3.1 base score is 6.5, reflecting network attack vector, low attack complexity, no privileges or user interaction required, and impacts on confidentiality and integrity.

An attacker can repeatedly attempt to authenticate using different passwords without limitation, increasing the likelihood of successfully guessing valid credentials. Successful exploitation results in unauthorized access to user accounts, potentially compromising sensitive information and device control. There is no indication of availability impact. No known exploits in the wild have been reported as of the publication date.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, it is recommended to implement external mitigations such as network-level access controls to restrict login attempts, use strong and unique passwords, and monitor authentication logs for suspicious activity. Avoid exposing the device's authentication interfaces directly to untrusted networks.