Overview
CVE-2025-47973 is a significant cybersecurity vulnerability involving a buffer over-read situation in Virtual Hard Disk (VHDX) systems. This vulnerability could potentially allow an attacker to gain unauthorized access and elevate privileges locally. The issue is particularly concerning for organizations utilizing virtualized environments, as it could lead to system compromise or data leakage.
Understanding and addressing this vulnerability promptly is crucial due to its severity. A successful exploit could lead to severe consequences, including unauthorized system access, sensitive data exposure, and potential system compromise. Such breaches could also lead to reputational damage and financial losses for affected organizations.
Vulnerability Summary
CVE ID: CVE-2025-47973
Severity: High (7.8 CVSS Score)
Attack Vector: Local
Privileges Required: None
User Interaction: None
Impact: System compromise and potential data leakage
Affected Products
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Product | Affected Versions
Microsoft Windows Server | 2012, 2016, 2019
Microsoft Hyper-V | All versions prior to October 2025
How the Exploit Works
The vulnerability involves a buffer over-read situation within the handling of VHDX files. An attacker could craft a malicious VHDX image and then mount it to exploit the vulnerability. This could lead to an out-of-bounds read, which might allow the attacker to obtain sensitive information from the host system or to execute arbitrary code with elevated privileges.
Conceptual Example Code
Here is a conceptual example of an exploit, assuming the attacker has local access to the system:
# Create a malicious VHDX image
vhdxtool create -size 10G -type dynamic -block 32K -log 1M malicious.vhdx
# Mount the VHDX image
mount -t vhdx -o loop malicious.vhdx /mnt/vhdx
# Interact with the system using the elevated privileges
whoami
Please note that the above is a conceptual example and will not work as is. It aims to illustrate the nature of the exploit.
Mitigation Guidance
To mitigate this vulnerability, organizations should apply the latest patches provided by the vendor. If a patch is not immediately available, using a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) can serve as a temporary mitigation measure. Regularly updating these systems and monitoring for any unusual activity can significantly decrease the risk of a successful exploit.