CVE-2025-52918 in YMCS
Summary
by MITRE • 06/22/2025
Yealink YMCS before 2025-05-26 does not prevent OpenAPI access by frozen enterprise accounts, allowing unauthorized access to deactivated interfaces.
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Analysis
by VulDB Data Team • 07/01/2025
The vulnerability identified as CVE-2025-52918 affects Yealink YMCS versions prior to the 2025-05-26 release, specifically targeting the OpenAPI access control mechanisms within the Yealink Management and Configuration System. This issue represents a critical authorization flaw that undermines the security posture of enterprise communication systems relying on Yealink devices. The vulnerability stems from insufficient account validation procedures that fail to properly revoke API access privileges when enterprise accounts are deactivated or frozen. This flaw allows malicious actors or compromised legitimate users to maintain access to deactivated interfaces through the OpenAPI, creating a persistent security risk that extends beyond the intended account lifecycle management.
The technical implementation of this vulnerability resides in the authentication and authorization framework of the YMCS platform, where the system does not adequately verify account status during OpenAPI access requests. When an enterprise account is frozen or deactivated, the system should immediately revoke all associated API access permissions, but this validation process is incomplete or absent in affected versions. The flaw operates at the interface level where API endpoints remain accessible even after account deactivation, bypassing normal access control checks that should validate account status before granting interface access. This represents a failure in proper access control implementation and demonstrates a lack of account lifecycle management within the system's security architecture.
The operational impact of CVE-2025-52918 extends beyond simple unauthorized access, creating potential for significant security breaches within enterprise environments. Attackers can exploit this vulnerability to access deactivated interfaces and potentially perform administrative functions, modify system configurations, or extract sensitive data from the communication infrastructure. The persistence of access through frozen accounts means that security incidents may remain undetected for extended periods, as compromised credentials or unauthorized access patterns could continue operating without proper account validation. This vulnerability directly impacts the principle of least privilege and can enable attackers to escalate privileges or maintain persistent access within the network, particularly in environments where Yealink devices are integrated with enterprise management systems.
Organizations affected by this vulnerability should immediately implement mitigations including updating to the patched version released on or after 2025-05-26, which addresses the account deactivation validation issue. Security teams should conduct comprehensive audits of all Yealink YMCS implementations to identify and disable any frozen or deactivated accounts that may still have active API access. Network monitoring should be enhanced to detect unusual API access patterns from potentially compromised accounts, and access logs should be reviewed for any unauthorized activity. The vulnerability aligns with CWE-631: "Weaknesses in Authorization" and represents a specific implementation of improper access control that can be categorized under ATT&CK technique T1078.004: "Valid Accounts: Cloud Accounts" when the affected systems integrate with cloud-based management interfaces, potentially enabling attackers to maintain access through frozen enterprise credentials. Additionally, this vulnerability may facilitate lateral movement within enterprise networks and could enable more sophisticated attacks such as credential theft or privilege escalation.