CVE-2025-24990: Microsoft Windows Untrusted Pointer Dereference Vulnerability

CVE-2025-24990 is an untrusted pointer dereference vulnerability in the Microsoft Windows Agere Modem Driver. Successful exploitation can allow an attacker to escalate privileges and gain administrator rights on the affected system. This matters because privilege escalation flaws in core Windows components can turn limited access into full control, enabling further persistence, lateral movement, or data access if an attacker already has a foothold.

Public detail is limited to the CISA summary and the CWE classification; exact affected builds, attack vectors, and scoring must be confirmed against the Microsoft vendor advisory before acting.

How it works

The weakness is classified as CWE-822 (Untrusted Pointer Dereference). In this class of flaw, software uses a pointer value that an attacker can influence or that originates from an untrusted source without sufficient validation. When the driver later dereferences that pointer, the result can be memory corruption or control-flow hijacking that elevates the attacker's privileges.

According to the CISA summary, the vulnerability resides in the Microsoft Windows Agere Modem Driver and allows privilege escalation to administrator. No further exploit mechanics, preconditions, or code-level details are provided in the available facts, so defenders should treat any public proof-of-concept claims with caution and rely on the vendor advisory for authoritative technical description.

Am I affected? How to find it in your systems

The vulnerability affects Microsoft Windows systems that include the Agere Modem Driver. This driver is typically associated with certain modem hardware and may be present on both client and server installations depending on hardware configuration and installed packages.

• Inventory Windows endpoints and servers for the presence of the Agere Modem Driver (look for related driver files, services, or device entries under modem or communications hardware).
• Compare installed Windows builds and driver versions against the list of affected and fixed versions published in the Microsoft advisory for CVE-2025-24990; do not assume any particular release is safe without that confirmation.
• Review configuration management and software inventory tools for systems that still load legacy modem drivers even if physical modem hardware is no longer in use.
• For exploitation signs, monitor for unexpected privilege escalations, anomalous process creation under elevated tokens, or crashes/hangs involving the modem driver. Specific telemetry indicators are not detailed in the available facts, so baseline normal driver behavior and alert on deviations.

How to remediate

The primary remediation is to apply the security update or mitigation instructions issued by Microsoft for CVE-2025-24990. CISA directs organizations to apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

• Deploy the vendor-supplied patch through your standard Windows Update, WSUS, or enterprise patch-management pipeline as soon as it is validated in your environment.
• After patching, verify that the Agere Modem Driver has been updated or removed as specified by Microsoft.
• As general hardening for this class of driver vulnerability, remove or disable unused modem and communications drivers, enforce least-privilege for local accounts, and keep the Windows kernel and related components current.

If you can't patch immediately

Until the vendor update can be applied, reduce exposure with compensating controls appropriate to an untrusted-pointer privilege-escalation flaw in a Windows driver.

• Segment systems that still require the Agere Modem Driver so they cannot easily reach high-value assets.
• If the modem functionality is not required, disable or uninstall the driver and associated services to eliminate the attack surface.
• Apply host-based controls that restrict loading of unsigned or unexpected drivers and that limit local privilege-escalation paths (for example, through application control or restricted admin rights).
• Increase monitoring for privilege-escalation activity and driver-related anomalies on unpatched hosts; consider temporary virtual-patching rules if your endpoint or network security tools support driver-behavior signatures for this class of issue.
• Follow any additional temporary workarounds listed in the Microsoft advisory once confirmed.

If your data may have been exposed

Actively exploited privilege-escalation vulnerabilities can lead to full system compromise and subsequent data exposure. Known ransomware use of this specific CVE is not documented in the available facts. If you suspect compromise, isolate affected hosts, preserve forensic evidence, and follow your incident-response process. Separately, you can run a free exposure scan of your email addresses against known breach data to determine whether credentials or personal information have appeared in prior public breaches.