CVE-2026-47876: VMXNET3 out-of-bounds write vulnerability | Rafael Pfister

Analysis on rafaelpfister.ch

Article · October 29, 2026 VMware ESX and Linux Kernel: CISA Reports Attacks on CVE-2026-41709 and Fragnesia On October 28, 2026, CISA added two vulnerabilities to its KEV catalog: CVE-2026-41709 in VMware ESX (operations without log entries, CVSS 2.7) and CVE-2026-46300 (Fragnesia) in the Linux kernel (privilege escalation, CVSS 7.8). Both have been used in real-world attack chains. Updates have been available for months.

Vendor description

VMware ESX contains an out-of-bounds write vulnerability in the VMXNET3 virtual network adapter. A malicious actor with local administrative privileges on a virtual machine with VMXNET3 virtual network adapter may exploit this issue to execute code on the host. Non VMXNET3 virtual adapters are not affected by this issue.

Reference data

Vendor

VMware

Affected products

Cloud Foundation
vSphere Foundation
ESX
Telco Cloud Platform

CVSS 3.1

9.3 (CRITICAL)

Vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Weakness type

CWE-787: Out-of-bounds Write

Published

July 30, 2026

Official sources

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