CVE-2025-26688 in Windows
Summary
by MITRE • 04/08/2025
Stack-based buffer overflow in Microsoft Virtual Hard Drive allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 05/31/2026
A stack-based buffer overflow vulnerability exists within Microsoft Virtual Hard Drive components that enables authenticated attackers to achieve local privilege escalation. This vulnerability stems from improper input validation and memory management practices within the virtualization software stack, creating an exploitable condition where malicious code can overwrite adjacent memory locations on the stack. The flaw typically manifests when the system processes malformed input data through virtual hard drive operations, particularly during disk image handling or virtual machine configuration processes. Attackers with legitimate user accounts can leverage this vulnerability to execute arbitrary code with elevated privileges, potentially gaining system-level access. The underlying technical mechanism involves stack pointer corruption and return address overwriting, allowing attackers to redirect execution flow to malicious payload locations. This vulnerability directly maps to common weakness enumeration CWE-121 stack-based buffer overflow, which is classified as a critical security flaw in software development practices. The attack vector requires local system access and authentication, making it a local privilege escalation vulnerability rather than a remote exploit. According to the attack technique framework, this represents a privilege escalation pathway under ATT&CK technique T1068, where adversaries leverage software vulnerabilities to gain higher-level permissions. The operational impact extends beyond simple code execution, as successful exploitation can lead to complete system compromise, data exfiltration, and persistent backdoor establishment. Organizations running virtualized environments are particularly at risk since the vulnerability exists within core virtualization components that handle disk image processing. The vulnerability's exploitation requires understanding of the target system architecture, memory layout, and stack organization, making it a sophisticated attack requiring significant technical expertise. Mitigation strategies should focus on applying vendor security patches promptly, implementing application whitelisting policies, and employing runtime protection mechanisms such as stack canaries and address space layout randomization. System administrators should also consider reducing the attack surface by disabling unnecessary virtualization features and monitoring for suspicious virtual hard drive operations. The vulnerability demonstrates the critical importance of secure coding practices in virtualization software development and highlights the need for comprehensive security testing of system components that handle user-supplied data. Regular security assessments and vulnerability scanning should include virtualization software components to identify similar memory corruption flaws that could be exploited for privilege escalation attacks.