CVE-2026-62751 in Windows
Summary
by MITRE • 08/11/2026
Integer overflow or wraparound in Windows Projected File System allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 08/11/2026
The vulnerability described represents a critical integer overflow condition within the Windows Projected File System component that enables local privilege escalation for authenticated attackers. This flaw exists in the handling of integer arithmetic operations within the file system projection mechanisms, where improper bounds checking allows integer wraparound conditions to occur during file system operations. The Projected File System functionality allows applications to present virtual file system content through projections, enabling dynamic content generation and access control enforcement. When integer overflow occurs in memory allocation calculations or buffer size determinations, it can lead to memory corruption that adversaries can exploit to gain elevated privileges.
The technical implementation of this vulnerability stems from insufficient input validation within the kernel-mode components responsible for managing projected file system operations. Specifically, when processing file attributes, directory enumeration, or access control list modifications, the system performs arithmetic operations on integer values representing buffer sizes, file offsets, or memory allocation requirements. An attacker with local user privileges can manipulate these inputs to cause integer wraparound, resulting in allocated buffers that are smaller than expected, creating potential for heap corruption or memory overwrite conditions. This vulnerability directly maps to CWE-190 Integer Overflow or Wraparound, which is classified under the weakness category of integer arithmetic errors in software systems.
The operational impact of this vulnerability extends beyond simple privilege escalation to potentially enable persistent access and lateral movement within compromised systems. Once elevated privileges are obtained through local exploitation, attackers can modify system files, install malware, establish backdoors, or access sensitive data that would otherwise be protected by standard access controls. The attack surface is particularly concerning because it requires only local authentication, meaning any user with login credentials can potentially exploit this vulnerability without requiring additional network access or specialized tools. This characteristic makes the vulnerability highly attractive to both malicious insiders and external attackers who have gained initial system access through other means.
Mitigation strategies for this vulnerability should include immediate deployment of Microsoft security patches that address the integer overflow conditions in the Projected File System implementation. System administrators should implement comprehensive monitoring for unusual file system operations or memory allocation patterns that might indicate exploitation attempts. The principle of least privilege should be enforced by restricting local user accounts from performing unnecessary file system operations that could trigger projection mechanisms. Additionally, implementing kernel-mode exploit protection features such as control flow guard and address space layout randomization can provide additional defense-in-depth measures against exploitation attempts. This vulnerability aligns with several ATT&CK techniques including privilege escalation through kernel exploits and local persistence mechanisms, making comprehensive endpoint detection and response capabilities essential for identifying potential exploitation activities. Organizations should also conduct regular security assessments to identify other potential integer overflow conditions within their Windows environments and ensure proper input validation across all system components.