CVE-2025-55335 is a use-after-free vulnerability classified under CWE-416, found in the Windows NTFS file system driver on Windows 10 Version 1809 (build 17763.0). The vulnerability arises from improper handling of memory objects within the NTFS driver, leading to a use-after-free condition. This flaw can be exploited by an unauthorized local attacker to execute arbitrary code with elevated privileges, effectively allowing privilege escalation from a non-privileged user context to SYSTEM level. The attack vector is local, requiring the attacker to have access to the system but no prior privileges or user interaction. The CVSS v3.1 score of 7.4 reflects high severity, with high impacts on confidentiality, integrity, and availability, but with high attack complexity and no privileges required initially. No public exploits are known at this time, but the vulnerability is critical due to the potential for full system compromise. The vulnerability affects legacy Windows 10 systems that may still be operational in enterprise environments, particularly those that have not been updated or are running in isolated or controlled networks. The lack of available patches at the time of publication increases the risk window. This vulnerability underscores the importance of timely patch management and system upgrades. The NTFS driver is a core component of Windows file system operations, so exploitation could disrupt file access and system stability, further amplifying the impact. Organizations relying on Windows 10 Version 1809 should prioritize mitigation and monitoring to prevent exploitation.

For European organizations, the impact of CVE-2025-55335 is significant. Successful exploitation allows an attacker with local access to escalate privileges to SYSTEM level, potentially leading to full control over affected systems. This can result in unauthorized data access, modification, or destruction, compromising confidentiality and integrity. Availability may also be affected if the exploit causes system crashes or instability. Critical sectors such as government, finance, healthcare, and industrial control systems that still operate legacy Windows 10 Version 1809 systems are particularly vulnerable. The vulnerability could be leveraged as a foothold for lateral movement within networks, increasing the risk of widespread compromise. Given the high attack complexity, exploitation is less trivial but remains a serious threat in environments where attackers gain local access through phishing, insider threats, or other means. The absence of known exploits currently provides a window for proactive defense, but organizations must act swiftly to mitigate risks. The impact is exacerbated in environments with weak endpoint security, insufficient monitoring, or delayed patching practices.

1. Apply official Microsoft security updates as soon as they become available for Windows 10 Version 1809 to remediate the use-after-free vulnerability in the NTFS driver. 2. If patches are not yet available, restrict local access to systems running this Windows version by enforcing strict access controls and limiting user privileges. 3. Implement application whitelisting and endpoint detection and response (EDR) solutions to detect and block suspicious activities indicative of privilege escalation attempts. 4. Monitor system logs and security events for unusual NTFS driver behavior or unexpected privilege escalations. 5. Consider upgrading affected systems to a supported and fully patched Windows version to reduce exposure to legacy vulnerabilities. 6. Conduct regular security audits and vulnerability assessments focusing on legacy systems to identify and remediate risks proactively. 7. Educate users about the risks of local access threats and enforce strong physical and network security controls to prevent unauthorized local access. 8. Use virtualization or sandboxing for high-risk applications to limit the impact of potential exploits.