CVE-2026-102218 in Windows
Summary
by MITRE • 10/13/2026
Heap-based buffer overflow in Windows Universal Disk Format File System Driver (UDFS) allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability identified involves a heap-based buffer overflow within the Windows Universal Disk Format File System Driver, commonly referred to as UDFS.sys. This component is responsible for managing file system operations on media formatted with the Universal Disk Format, which is frequently used for optical discs such as DVDs and Blu-ray disks. The core technical flaw stems from improper bounds checking during memory allocation or data copying operations within the driver's kernel-mode execution context. When an application interacts with a UDFS-formatted volume, specifically through file system requests that involve specific metadata structures or path manipulations, the driver may fail to validate the length of input data against the allocated heap buffer size. This lack of rigorous validation allows an attacker to supply crafted input that exceeds the expected boundaries, causing data to overflow into adjacent memory regions on the kernel heap.
The operational impact of this vulnerability is severe due to its potential for local privilege escalation. Because UDFS.sys operates at ring 0 with high-level system privileges, a successful exploitation of this buffer overflow grants an attacker arbitrary code execution capabilities within the kernel space. By carefully crafting the overflow payload, an authorized user can overwrite critical control data structures such as function pointers or exception handlers on the heap. This manipulation allows the attacker to redirect the flow of execution to malicious shellcode injected into the process memory. Consequently, this leads to a complete compromise of system integrity, enabling the elevation of privileges from a standard user account to that of SYSTEM or Administrator. The attacker gains full control over the operating system, which can be leveraged for further lateral movement, data exfiltration, persistence mechanisms, and disabling security controls.
From a threat modeling perspective, this vulnerability aligns with CWE-122: Heap-based Buffer Overflow, as it involves writing beyond the allocated heap memory boundaries. The exploitation technique typically falls under MITRE ATT&CK Technique T1068: Exploitation for Privilege Escalation, where an attacker leverages a software flaw to gain higher-level access rights. Additionally, since the vulnerability resides in a kernel driver, it relates to CWE-254: Security Features Bypass and potentially CWE-787: Out-of-bounds Write depending on the specific memory corruption mechanism employed during exploitation. The attack vector is classified as local (AV:L), meaning physical or logical access to the machine with valid credentials is required initially, but the subsequent impact significantly expands the risk profile by breaking the isolation between user-mode applications and kernel-mode components.
Mitigation strategies for this vulnerability primarily involve applying vendor-supplied security patches that address the input validation logic within UDFS.sys. System administrators should ensure that all Windows systems are updated with the latest cumulative updates released by Microsoft, which typically include fixes for such driver-level flaws. In environments where immediate patching is not feasible, reducing the attack surface can help mitigate risk. This includes disabling unnecessary file system drivers if optical media support is not required, although this may impact functionality related to DVD or Blu-ray drives. Furthermore, implementing strict application whitelisting and monitoring kernel-mode activity for anomalous behavior using Endpoint Detection and Response (EDR) solutions can provide an additional layer of defense against exploitation attempts. Regular auditing of user permissions and enforcing the principle of least privilege also reduces the likelihood that a compromised low-privilege account can successfully trigger this vulnerability to achieve administrative access.