CVE-2025-48816 is a high-severity vulnerability identified in Microsoft Windows 10 Version 1809 (build 10.0.17763.0) involving an integer overflow or wraparound issue within the Human Interface Device (HID) class driver. The vulnerability stems from improper handling of integer values, specifically a failure to correctly validate or limit integer operations, leading to an overflow condition. This flaw can be exploited by an authorized local attacker to elevate privileges on the affected system. The HID class driver is responsible for managing input devices such as keyboards, mice, and other human interface peripherals. An integer overflow in this context could allow an attacker to manipulate memory or control flow, bypassing security restrictions and gaining higher privileges than originally granted. The CVSS v3.1 base score of 7.8 reflects a high severity, with the vector indicating local attack vector (AV:L), low attack complexity (AC:L), requiring low privileges (PR:L), no user interaction (UI:N), unchanged scope (S:U), and high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). No known exploits are currently reported in the wild, and no patches or mitigations have been linked yet, indicating that this is a newly published vulnerability. The vulnerability is categorized under CWE-190 (Integer Overflow or Wraparound), which often leads to memory corruption and security bypasses. Given that the vulnerability requires local access and low privileges, it is particularly dangerous in environments where multiple users share systems or where attackers can gain initial footholds with limited permissions. Exploiting this flaw could allow attackers to escalate privileges to SYSTEM or equivalent, enabling full control over the affected machine.

For European organizations, this vulnerability poses a significant risk, especially in sectors relying heavily on Windows 10 Version 1809 systems, such as government, finance, healthcare, and critical infrastructure. Privilege escalation vulnerabilities can facilitate lateral movement within networks, data exfiltration, deployment of ransomware, or sabotage of critical systems. Since the vulnerability affects a core driver managing input devices, exploitation could be stealthy and difficult to detect. Organizations with legacy systems or delayed patching policies are particularly vulnerable. The impact extends to confidentiality, integrity, and availability, potentially leading to full system compromise. Additionally, environments with shared workstations or remote access solutions that allow local user access are at increased risk. The lack of known exploits currently provides a window for proactive mitigation, but the high severity score suggests attackers may develop exploits rapidly. Compliance with European data protection regulations (e.g., GDPR) could be jeopardized if this vulnerability is exploited to access or manipulate sensitive personal data.

Given the absence of an official patch at the time of this report, European organizations should implement the following specific mitigations: 1) Restrict local user access strictly to trusted personnel and minimize the number of users with local login privileges on systems running Windows 10 Version 1809. 2) Employ application whitelisting and endpoint detection and response (EDR) solutions to monitor and block suspicious activities indicative of privilege escalation attempts. 3) Harden systems by disabling or restricting unnecessary HID devices where feasible, reducing the attack surface related to the HID class driver. 4) Conduct thorough audits of user privileges and remove or limit accounts with low privileges that could be leveraged for local attacks. 5) Implement network segmentation to contain potential compromises and prevent lateral movement. 6) Monitor system logs and security event data for anomalies related to driver behavior or unusual privilege escalations. 7) Prepare for rapid deployment of official patches once released by Microsoft and test them in controlled environments before widespread rollout. 8) Educate IT staff and users about the risks of local privilege escalation and enforce strict endpoint security policies. These targeted measures go beyond generic advice by focusing on controlling local access, monitoring HID-related activities, and preparing for patch management.