CVE-2026-49790 in Windows
Summary
by MITRE • 07/14/2026
Windows Universal Disk Format File System Driver (UDFS) Elevation of Privilege Vulnerability
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Analysis
by VulDB Data Team • 07/15/2026
This vulnerability exists within the Windows Universal Disk Format File System Driver component that handles UDFS file operations and is categorized as an elevation of privilege flaw under cwe-264. The technical implementation flaw stems from insufficient validation of user-supplied data during UDFS file system operations, allowing malicious actors to manipulate kernel-mode drivers through crafted file system structures. The vulnerability specifically affects the way the UDFS driver processes certain metadata fields and file allocation patterns, creating opportunities for privilege escalation when legitimate user processes interact with malformed UDFS volumes.
The operational impact of this vulnerability enables an attacker with low-privilege access to potentially escalate their privileges to SYSTEM level within the Windows operating system. This occurs because the kernel-mode driver lacks proper input sanitization mechanisms that would normally prevent malicious data from being processed in privileged contexts. Attackers can exploit this by creating specially crafted UDFS file system structures or manipulating existing UDFS volumes to trigger the vulnerable code path, ultimately leading to arbitrary code execution within kernel space. The flaw is particularly dangerous because it operates at the file system driver level where normal user-mode restrictions do not apply.
From a cybersecurity perspective, this vulnerability aligns with attack patterns documented in the attack mitigation framework where adversaries seek to leverage kernel-level flaws for privilege escalation. The vulnerability's exploitation typically requires the attacker to have some form of local access or ability to mount malicious UDFS volumes, making it more prevalent in scenarios involving removable media or network file shares. Organizations should consider implementing the principle of least privilege alongside regular patch management protocols to mitigate against potential exploitation attempts.
The remediation approach involves applying official microsoft security updates that address the input validation gaps within the UDFS driver implementation. System administrators should prioritize deployment of these patches across all affected systems, particularly those handling removable media or network file shares. Additionally, implementing additional monitoring controls around file system driver activity and user privilege changes can help detect potential exploitation attempts. The vulnerability serves as a reminder of the critical importance of kernel-mode security validation and proper input sanitization in operating system components that handle external data structures.
This flaw demonstrates how legacy file system drivers can contain security vulnerabilities that persist across multiple versions of operating systems, highlighting the need for continuous security assessment of core operating system components. Organizations should maintain comprehensive asset inventories that track all systems with UDFS support capabilities and ensure regular security assessments to identify similar kernel-level vulnerabilities. The vulnerability also underscores the importance of layered defensive strategies where multiple security controls work together to protect against privilege escalation attacks targeting core operating system functionality.
Reference to cwe-264 indicates this vulnerability involves improper privileges assignment within kernel-mode operations, while attack patterns in the attack framework show similar exploitation techniques targeting file system drivers for privilege escalation. The security implications extend beyond immediate privilege escalation to potential persistence mechanisms and lateral movement capabilities that attackers might leverage once elevated privileges are obtained through such vulnerabilities.