A heap-based buffer overflow exists in the Windows Universal Disk Format File System Driver (UDFS). When a user with sufficient permissions can write data to a UDFS volume, the driver fails to validate the size of the buffer, enabling the attacker to inject arbitrary data. The overflow can be exploited to execute code in kernel mode, thereby allowing the attacker to elevate privileges on the local system. The weakness is categorized as CWE‑122.

The vulnerability impacts Microsoft Windows 10 versions 1607, 1809, 21H2, 22H2 and Windows 11 versions 23H2, 24H2, 25H2, 26H1, as well as Microsoft Windows Server releases 2012 through 2025. All listed releases include the UDFS driver and are therefore affected.

The CVSS base score of 7.8 indicates a high severity. EPSS data is not available, and the issue is not listed in the CISA KEV catalog. Attackers must be authorized to the local machine to trigger the overflow, likely through access to a removable media device formatted with UDFS. Once exploited, the attacker gains kernel‑level privileges, potentially compromising confidentiality, integrity, and availability of the affected system.