CVE-2025-52916 in YMCS RPS
Summary
by MITRE • 06/22/2025
Yealink YMCS RPS before 2025-06-04 lacks SN verification attempt limits, enabling brute-force enumeration (last five digits).
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 07/01/2025
The vulnerability identified as CVE-2025-52916 affects Yealink YMCS RPS versions prior to the 2025-06-04 release, presenting a significant security weakness in the authentication mechanism. This issue specifically targets the lack of secure network verification attempt limits within the system, creating an exploitable condition that allows malicious actors to perform brute-force enumeration attacks. The vulnerability is particularly concerning as it enables attackers to systematically guess and test the last five digits of serial numbers, which are often used as part of the authentication process or as identifiers within the device management framework.
The technical flaw stems from the absence of rate limiting or account lockout mechanisms during the SN verification process. When users attempt to authenticate or verify serial numbers, the system does not implement proper controls to prevent rapid successive attempts, allowing for automated brute-force attacks to proceed unchecked. This weakness directly maps to CWE-307, which addresses inadequate account lockout mechanisms, and represents a classic example of insufficient brute-force protection in authentication systems. The vulnerability exposes the underlying assumption that serial number verification can be performed without any protective measures against automated attack vectors.
The operational impact of this vulnerability extends beyond simple unauthorized access attempts, as it creates opportunities for broader reconnaissance and system compromise. Attackers can systematically enumerate serial numbers to identify valid devices within the network, potentially leading to unauthorized device management access, data exfiltration, or even device takeover scenarios. The last five digits of serial numbers often contain predictable patterns or are derived from sequential numbering systems, making them particularly vulnerable to systematic guessing attacks. This vulnerability can be leveraged as a stepping stone for more sophisticated attacks, potentially enabling lateral movement within networks or access to additional system components that rely on the same authentication infrastructure.
Mitigation strategies should focus on implementing robust rate limiting mechanisms, account lockout policies, and monitoring for suspicious authentication patterns. Organizations should immediately update their Yealink YMCS RPS systems to the latest version released on or after 2025-06-04, which should include proper SN verification attempt limits. Additional protective measures include implementing network-level controls to restrict access to authentication endpoints, deploying intrusion detection systems to monitor for brute-force patterns, and establishing monitoring procedures to detect unusual authentication activity. The implementation of multi-factor authentication and stronger credential management practices would further reduce the risk associated with this vulnerability, aligning with ATT&CK technique T1110 for credential access through brute force methods. Organizations should also consider implementing automated systems to detect and respond to rapid authentication attempts, as this vulnerability demonstrates the critical importance of protecting authentication mechanisms from automated attack vectors that can be easily exploited without significant technical sophistication.