Executive Summary
A critical vulnerability (CVE-2026-77178) with a CVSS score of 9.1 has been discovered in Oracle VM VirtualBox before version 7.2.8. This vulnerability allows guest OS users to cause an out-of-bounds write in the host OS, potentially leading to high impact on integrity and availability. Administrators should update VirtualBox to version 7.2.8 or later immediately.
Technical Analysis
CVE-2026-77178 is a vulnerability in the PCNet (Am79C970A) network device model of Oracle VM VirtualBox, specifically in the pcnetReceiveNoSync function in DevPCNet.cpp. The vulnerability class is an out-of-bounds write, which occurs when the guest OS user sends a specially crafted network packet to the PCNet device. The attack vector is network-based, with low attack complexity and no required privileges or user interaction.
How It Gets Exploited
An attacker with access to a guest OS on a vulnerable VirtualBox instance can exploit this vulnerability by sending a crafted network packet to the PCNet device. Specifically, the attacker would send a packet that triggers the pcnetReceiveNoSync function to write data beyond the bounds of a buffer, potentially allowing the attacker to execute arbitrary code on the host OS or cause a denial-of-service condition.
Impact Assessment
The vulnerability affects Oracle VM VirtualBox versions before 7.2.8. Successful exploitation could lead to high impact on integrity and availability of the host OS. The CVSS score for this vulnerability is 9.1, indicating a critical severity level.
Recommended Actions
To mitigate this vulnerability, administrators should update Oracle VM VirtualBox to version 7.2.8 or later. Additionally, administrators can consider implementing network segmentation or restricting access to the VirtualBox instance to reduce the attack surface.
Sources
- National Vulnerability Database (NVD)
- Oracle VM VirtualBox