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, also known as wrap or wraparound, which occurs when an arithmetic operation causes a variable to wrap around its minimum value, leading to unexpected behavior. Specifically, the flaw exists in the MBT Transport driver component of Windows 10 build 17763.0. An authorized local attacker with limited privileges (PR:L) can exploit this vulnerability to elevate their privileges on the affected system without requiring user interaction (UI:N). The CVSS v3.1 base score is 7.8, indicating a high severity level, with impacts on confidentiality, integrity, and availability (all rated high). The attack vector is local (AV:L), meaning the attacker must have local access to the system, but the attack complexity is low (AC:L), and no user interaction is needed. The vulnerability allows an attacker to manipulate the integer value in such a way that memory corruption or logic errors occur, potentially enabling them to execute arbitrary code or gain SYSTEM-level privileges. Although no known exploits are currently reported in the wild, the vulnerability's characteristics make it a significant risk if weaponized. No patch links are provided yet, suggesting that mitigation may rely on workarounds or awaiting official updates. The vulnerability was reserved in May 2025 and published in July 2025, indicating recent discovery and disclosure.

For European organizations, this vulnerability poses a substantial risk, especially in environments where Windows 10 Version 1809 is still in use, such as legacy systems or specialized industrial setups. Successful exploitation could allow attackers to escalate privileges locally, bypassing security controls and gaining administrative access. This could lead to unauthorized access to sensitive data, disruption of critical services, and potential lateral movement within corporate networks. The high impact on confidentiality, integrity, and availability means that data breaches, system tampering, and denial of service are plausible outcomes. Given that the attack requires local access, insider threats or attackers who have already compromised lower-privileged accounts could leverage this vulnerability to deepen their foothold. European organizations in sectors like finance, healthcare, manufacturing, and government, where Windows 10 1809 may still be operational, are particularly at risk. The lack of known exploits in the wild currently provides a window for proactive mitigation before widespread exploitation occurs.

1. Immediate mitigation should focus on identifying and inventorying all systems running Windows 10 Version 1809 (build 17763.0) within the organization. 2. Apply any available Microsoft security updates or patches as soon as they are released; monitor official Microsoft channels for patch announcements related to CVE-2025-47996. 3. If patches are not yet available, consider isolating or restricting access to affected systems to minimize local access by unauthorized users. 4. Implement strict access controls and monitoring to detect and prevent unauthorized local logins or privilege escalations. 5. Employ application whitelisting and endpoint detection and response (EDR) solutions to identify suspicious behavior indicative of exploitation attempts. 6. Educate internal users and administrators about the risks of local privilege escalation vulnerabilities and enforce the principle of least privilege to reduce the attack surface. 7. For legacy systems that cannot be upgraded promptly, consider virtual patching or compensating controls such as enhanced logging and network segmentation to limit potential damage. 8. Regularly review and update incident response plans to include scenarios involving local privilege escalation vulnerabilities.