CVE-2025-54916 is a high-severity stack-based buffer overflow vulnerability identified in the Windows NTFS component of Microsoft Windows 10 Version 1809 (build 10.0.17763.0). This vulnerability is classified under CWE-121, which pertains to improper handling of buffer boundaries leading to stack-based buffer overflows. The flaw allows an authorized local attacker—meaning the attacker must have some level of legitimate access to the affected system—to execute arbitrary code with elevated privileges. The vulnerability arises from improper validation or bounds checking in the NTFS file system driver, which processes file system metadata and operations. Exploiting this vulnerability could enable an attacker to overwrite critical memory regions on the stack, potentially leading to arbitrary code execution, complete compromise of system integrity, and disruption of availability. The CVSS v3.1 base score is 7.8, indicating a high severity level, with the vector string AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, meaning the attack requires local access with low complexity, privileges, and no user interaction, and impacts confidentiality, integrity, and availability to a high degree. There are no known exploits in the wild at the time of publication, and no patches have been linked yet. The vulnerability was reserved on July 31, 2025, and published on September 9, 2025. Given the affected product is Windows 10 Version 1809, which is an older release, many organizations may have already moved to newer versions, but legacy systems remain at risk. The lack of user interaction and the ability to gain high-impact code execution make this vulnerability particularly dangerous in environments where local access can be obtained, such as multi-user systems or environments with weak endpoint security controls.

For European organizations, the impact of CVE-2025-54916 can be significant, especially in sectors relying on legacy Windows 10 Version 1809 systems. Successful exploitation could lead to full system compromise, allowing attackers to steal sensitive data, disrupt critical services, or establish persistent footholds within networks. This is particularly concerning for industries such as finance, healthcare, manufacturing, and government agencies, where confidentiality and integrity of data are paramount. The vulnerability’s requirement for local access limits remote exploitation but does not eliminate risk, as insider threats, compromised credentials, or lateral movement within networks could enable attackers to leverage this flaw. Additionally, organizations with Bring Your Own Device (BYOD) policies or less controlled endpoint environments may face higher exposure. The high impact on confidentiality, integrity, and availability means that exploitation could result in data breaches, operational downtime, and regulatory non-compliance under frameworks like GDPR. The absence of known exploits currently provides a window for proactive mitigation, but the potential for future weaponization necessitates urgent attention.

Given the absence of an official patch at the time of analysis, European organizations should implement several targeted mitigations: 1) Identify and inventory all systems running Windows 10 Version 1809 to assess exposure. 2) Restrict local access to critical systems by enforcing strict access controls, including the use of least privilege principles and multi-factor authentication for local logins. 3) Employ endpoint detection and response (EDR) solutions capable of monitoring for anomalous behavior indicative of exploitation attempts, such as unusual NTFS activity or memory corruption indicators. 4) Harden systems by disabling unnecessary local accounts and services that could be leveraged to gain local access. 5) Implement network segmentation to limit lateral movement opportunities if an attacker gains local access on one machine. 6) Prepare for rapid deployment of patches once Microsoft releases an official fix by establishing a tested update management process. 7) Conduct user training to reduce insider threat risks and encourage reporting of suspicious activity. 8) Utilize application whitelisting and exploit mitigation technologies such as Control Flow Guard (CFG) and Data Execution Prevention (DEP) to reduce the likelihood of successful code execution. These measures go beyond generic advice by focusing on limiting local access vectors and enhancing detection capabilities specific to this vulnerability’s exploitation method.