Microsoft Windows Agere Modem Driver Vulnerability Allowing Elevation of Privilege

A vulnerability has been identified in the Agere Modem driver, which is included with supported Windows operating systems. This issue allows for elevation of privilege. The driver, ltmdm64.sys, has been removed in the October 2025 cumulative update. As a result, fax modem hardware relying on this driver will no longer function on Windows. Microsoft advises users to eliminate any dependencies on this hardware.

Impact

Exploitation of this vulnerability could lead to unauthorized elevation of privileges, allowing a user to gain administrator rights.

Remediation

Users can download the October 2025 cumulative update, which removes the vulnerable driver, through the Microsoft Update Catalog. For specific guidance on this update, refer to the Microsoft Knowledge Base articles KB5066873, KB5066875, KB5066872, KB5066876, KB5066780, KB5066793, KB5066791, KB5066586, and KB5066836.