VMware ESX EUVD-2026-51105

Exploitation requires (1) a virtual machine configured with the VMXNET3 virtual network adapter - VMs using any other virtual NIC are explicitly not affected - and (2) local administrative privileges inside that guest VM, per the vendor description. What limits exploitation: the attacker must already fully control a guest (no remote/network path to the host, AV:L), the target VM must specifically use VMXNET3, and the affected component is the ESX hypervisor stack. Note the tension with the CVSS PR:N rating, which does not reflect the guest-admin requirement stated in the description; defenders should treat guest administrative access as a de facto prerequisite.

The CVSS 3.1 score is 9.3 (Critical) with vector AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H: local attack vector, low complexity, no user interaction, and a scope change reflecting the guest-to-host escape with full confidentiality, integrity, and availability impact on the host. There is a notable conflict between the vendor's PR:N (no privileges) and the description, which explicitly requires 'local administrative privileges on a virtual machine' - verify with vendor; the PR:N likely reflects VMware's convention of scoring from the host's perspective (guest admin is still 'unprivileged' relative to the hypervisor), but in practice an attacker must first fully control a guest VM. No EPSS score, KEV entry, or POC was provided, so there is no public exploit identified at time of analysis and no evidence of active exploitation. Real-world priority is high for any multi-tenant or security-sensitive virtualization estate because the impact (hypervisor compromise / VM escape) is severe, even though the local-only vector and requirement to own a guest VM limit the population of viable attackers to those who already hold a foothold inside a VM.

An attacker who has already gained administrative control of a guest VM (via prior compromise, a rogue tenant, or a malicious insider) loads a crafted VMXNET3 driver sequence or sends malformed device operations that trigger the out-of-bounds write in the host-side adapter emulation. By shaping the corruption, they achieve code execution in the hypervisor process, escaping the VM to control the ESX host and, by extension, other VMs on it. No public exploit code has been identified at time of analysis, and the low-complexity local vector means no user interaction is required once guest admin is held.