CVE-2026-50357 in Windows
Summary
by MITRE • 07/14/2026
Numeric truncation error in Windows Resilient File System (ReFS) allows an authorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 07/14/2026
The vulnerability described represents a critical numeric truncation error within the Windows Resilient File System implementation that enables local code execution by authorized users. This flaw exists in the way ReFS handles numerical values during file system operations, creating a pathway for privilege escalation and arbitrary code injection. The issue stems from insufficient input validation and improper handling of integer overflow conditions within the file system's internal processing mechanisms.
From a technical perspective, this vulnerability manifests when the ReFS subsystem processes numeric data structures that exceed their allocated storage capacity, causing automatic truncation of values without proper bounds checking. The flaw typically occurs during metadata operations, file allocation calculations, or disk space management routines where integer values are manipulated and stored in fixed-width data types. When these operations encounter values that exceed maximum representable limits, the system silently truncates them to fit within available storage, potentially creating exploitable conditions.
The operational impact of this vulnerability extends beyond simple local privilege escalation as it provides attackers with a reliable method for executing arbitrary code within the context of the file system's privileged processes. Authorized users who can interact with ReFS volumes gain the ability to manipulate numerical parameters in ways that trigger the truncation error, potentially leading to memory corruption and code execution. This represents a significant concern for enterprise environments where ReFS is deployed for high-availability storage solutions.
Security researchers have identified this vulnerability as aligning with CWE-190, Integer Overflow or Wraparound, which specifically addresses issues where integer arithmetic results in values that exceed the maximum representable value for the data type. The exploitability of such conditions often maps to ATT&CK technique T1068, Exploitation for Privilege Escalation, as attackers can leverage these numeric errors to gain elevated system privileges.
Mitigation strategies for this vulnerability include applying Microsoft's security patches and updates that address the specific integer handling routines within ReFS. System administrators should prioritize deployment of these updates across all affected Windows systems running ReFS volumes. Additionally, implementing proper monitoring for unusual file system operations and numerical anomalies can help detect potential exploitation attempts. Organizations should also consider restricting unnecessary administrative access to ReFS volumes and implementing principle of least privilege controls to minimize the attack surface available to authorized users who might attempt to exploit this vulnerability.