CVE-2026-50318 in Windows
Summary
by MITRE • 07/14/2026
Stack-based buffer overflow in Windows Resilient File System (ReFS) allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 07/14/2026
A stack-based buffer overflow vulnerability exists within the Windows Resilient File System implementation that enables authenticated attackers to achieve local privilege escalation. This flaw resides in how ReFS handles certain file operations and memory management routines, creating a condition where crafted input data can overwrite adjacent stack memory locations. The vulnerability specifically manifests when the file system processes malformed or specially constructed file metadata during read or write operations. Attackers exploiting this weakness can manipulate stack variables and potentially overwrite return addresses, enabling arbitrary code execution within the context of the compromised process.
The technical nature of this vulnerability aligns with common CWE categories including CWE-121 Stack-based Buffer Overflow and CWE-787 Out-of-bounds Write. The attack vector requires local authentication since the vulnerability exists within the kernel-mode file system driver components that are accessible only to authenticated users. This characteristic places the flaw in the ATT&CK framework under privilege escalation techniques, specifically leveraging Windows File System and kernel-level vulnerabilities for lateral movement and persistence within compromised systems.
The operational impact of this vulnerability extends beyond simple privilege elevation as it provides attackers with a reliable mechanism to gain higher system privileges without requiring additional attack surfaces or complex exploitation chains. Once exploited, the attacker can execute code with elevated permissions, potentially accessing sensitive system resources, modifying critical files, or establishing persistent backdoors within the Windows environment. The ReFS file system's resilience characteristics that make it attractive for enterprise deployments actually compound the risk since administrators may not expect such vulnerabilities to exist in these supposedly robust storage solutions.
Mitigation strategies should focus on immediate patch deployment through Microsoft security updates, which address the underlying buffer overflow condition in the ReFS implementation. System administrators should also implement principle of least privilege controls, limiting user access to file system operations that could trigger the vulnerable code paths. Additional protective measures include monitoring for suspicious file system activity and implementing kernel-mode exploit detection mechanisms. Organizations should conduct thorough vulnerability assessments to identify systems running ReFS and prioritize remediation efforts accordingly. The vulnerability demonstrates the critical importance of securing all system components including storage subsystems, as even enterprise-grade file systems can contain exploitable conditions that compromise overall system security posture.