CVE-2025-47996 is a high-severity integer underflow vulnerability (CWE-191) found in the Microsoft Windows 10 Version 1809 MBT Transport driver. This vulnerability arises due to an integer underflow condition, where arithmetic operations cause the integer value to wrap around, leading to unexpected behavior. Specifically, the flaw exists in the MBT Transport driver component, which is part of the Windows networking stack. An authorized attacker with local access and low privileges can exploit this vulnerability to escalate their privileges to SYSTEM level, thereby gaining full control over the affected system. The vulnerability does not require user interaction but does require the attacker to have some level of local access (local privilege). The CVSS v3.1 base score is 7.8, indicating a high severity with high impact on confidentiality, integrity, and availability. The vulnerability was reserved in May 2025 and published in July 2025, with no known exploits in the wild at the time of publication. No official patches or mitigation links have been provided yet, which suggests that affected organizations need to be vigilant and consider interim mitigations. The flaw is specific to Windows 10 Version 1809 (build 10.0.17763.0), which is an older version of Windows 10, and may still be in use in some environments, especially in legacy or industrial systems.

For European organizations, the impact of this vulnerability can be significant, especially in environments where Windows 10 Version 1809 is still deployed. Successful exploitation allows an attacker with local access to escalate privileges to SYSTEM level, potentially leading to full system compromise. This could enable attackers to bypass security controls, access sensitive data, install persistent malware, or disrupt critical services. Sectors such as finance, healthcare, manufacturing, and government agencies that rely on legacy Windows 10 systems could face increased risk. The vulnerability's ability to compromise confidentiality, integrity, and availability simultaneously makes it particularly dangerous. Moreover, the lack of user interaction requirement facilitates automated or scripted exploitation once local access is obtained. Although no known exploits are currently in the wild, the high severity and ease of exploitation (low complexity, no UI required) mean that attackers may develop exploits rapidly. This risk is exacerbated in environments with weak local access controls or where endpoint security solutions do not adequately monitor or restrict driver-level operations.

Given the absence of official patches, European organizations should prioritize the following mitigations: 1) Upgrade or migrate systems from Windows 10 Version 1809 to a supported, patched version of Windows 10 or Windows 11 to eliminate exposure. 2) Restrict local access to systems by enforcing strict access control policies, including limiting administrative privileges and using least privilege principles. 3) Employ application whitelisting and endpoint detection and response (EDR) solutions to monitor and block suspicious driver-level activities or privilege escalation attempts. 4) Harden systems by disabling or restricting the MBT Transport driver if it is not required for business operations, through device or driver management policies. 5) Conduct regular audits of local user accounts and remove or disable unnecessary accounts to reduce the attack surface. 6) Monitor system and security logs for unusual activities indicative of privilege escalation attempts. 7) Prepare incident response plans specifically addressing local privilege escalation scenarios to enable rapid containment and remediation. These targeted mitigations go beyond generic advice by focusing on controlling local access, driver management, and proactive monitoring tailored to this vulnerability's characteristics.