CVE-2025-62457: 
vulnerability analysis and mitigation

CVE-2025-62457 is an out-of-bounds read vulnerability in the Windows Cloud Files Mini Filter Driver that allows an authorized local attacker to elevate privileges. It was disclosed and patched on December 9, 2025, as part of Microsoft's December 2025 Patch Tuesday security update release. Affected products span a wide range of Windows versions, including Windows 10 (1809, 21H2, 22H2), Windows 11 (23H2, 24H2, 25H2), Windows Server 2019, 2022, 2022 23H2, and Windows Server 2025. The vulnerability carries a CVSS v3.1 base score of 7.8 (High) (Microsoft MSRC, Tenable).

The root cause is classified as CWE-125 (Out-of-bounds Read) within the Windows Cloud Files Mini Filter Driver (cldflt.sys), a kernel-mode driver responsible for supporting cloud-backed file placeholders (e.g., OneDrive integration). An attacker with low-privileged local access can trigger an out-of-bounds read condition in this driver, which can be leveraged to escalate privileges to SYSTEM level. The attack vector is local, requires low privileges, and no user interaction, making it straightforward to exploit once an attacker has a foothold on the system. No public proof-of-concept code has been identified at the time of disclosure (Microsoft MSRC, Tenable).

Successful exploitation allows a low-privileged local attacker to elevate their privileges, potentially achieving SYSTEM-level access on the affected Windows host. This results in high confidentiality, integrity, and availability impact — an attacker could read sensitive data, modify system files, install malware, or disable security controls. The broad scope of affected Windows versions (desktop and server) means a large number of enterprise and consumer systems are at risk, and privilege escalation could facilitate lateral movement within a network if combined with other attack techniques (Microsoft MSRC, Tenable).

Microsoft released patches for CVE-2025-62457 on December 9, 2025, as part of the December 2025 Patch Tuesday update. Organizations should apply the relevant cumulative updates to bring affected systems to the following minimum build versions: Windows 10 1809/Server 2019 → 10.0.17763.8146; Windows 10 21H2 → 10.0.19044.6691; Windows 10 22H2 → 10.0.19045.6691; Windows 11 23H2 → 10.0.22631.6345; Windows 11 24H2/Server 2025 → 10.0.26100.7392 (or 10.0.26100.7462 per ENISA); Windows 11 25H2 → 10.0.26200.7392; Windows Server 2022 → 10.0.20348.4467; Windows Server 2022 23H2 → 10.0.25398.2025. As a defense-in-depth measure, organizations should enforce least-privilege principles, restrict local user access, and monitor for suspicious privilege escalation activity (Microsoft MSRC, Tenable).

The vulnerability was covered as part of broader December 2025 Patch Tuesday roundups by multiple security vendors and researchers. Tenable, Sophos, Zero Day Initiative (ZDI), and BleepingComputer all included it in their patch Tuesday analyses, noting it as one of several local privilege escalation vulnerabilities addressed in the release. No specific researcher commentary or notable social media discussion focused exclusively on CVE-2025-62457 was identified, as attention was primarily directed at the three zero-days patched in the same update cycle (BleepingComputer, ZDI, Sophos).