# CVE-2026-47876: VMware ESX out-of-bounds write in VMXNET3 adapter

Source: https://junglewise.ai/threats/cve-2026-47876-vmware-esx-out-of-bounds-write-in-vmxnet3-adapter  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-30. Updated: 2026-07-30  
License: CC BY 4.0 with a link back

CVE-2026-47876 · Severity: critical · CVSS 9.3 · Published 2026-07-30

VMware ESX is a virtualization platform used to run multiple virtual servers on a single physical machine. A vulnerability in the VMXNET3 virtual network adapter allows a user with administrative control over a single virtual machine to break out of that environment and execute commands on the underlying host server. This could lead to a total compromise of all other virtual machines running on the same physical hardware.

Technologies: [VMware Cloud Foundation](https://junglewise.ai/threats/technologies/cloud-foundation), [VMware ESXi](https://junglewise.ai/threats/technologies/esxi), [VMware vSphere Foundation](https://junglewise.ai/threats/technologies/vsphere-foundation). Vendors: [VMware](https://junglewise.ai/threats/vendors/vmware).

## Quick answers

**Is CVE-2026-47876 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-47876 being exploited in the wild.

**How severe is CVE-2026-47876?** Critical severity, with a CVSS score of 9.3, published 30 July 2026.

**Which products and versions are affected?** VMware Cloud Foundation 5.x, 9.0.x.x, 9.1.x.x; VMware ESX 8.0 before ESXi80U3k-25595708, 9.0.x.x before ESXi-9.0.2.0100-25595025, 9.1.x.x before ESXi-9.1.0.0200-25557999; VMware ESXi 8.0 before ESXi80U3k-25595708, 9.0.x.x before ESXi-9.0.2.0100-25595025, 9.1.x.x before ESXi-9.1.0.0200-25557999; VMware vSphere Foundation 9.0.x.x, 9.1.x.x.

**Is there a fix for CVE-2026-47876?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-47876 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-47876?** Check whether you run VMware Cloud Foundation, VMware ESX, VMware ESXi or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An out-of-bounds write vulnerability (CWE-787) exists in the VMXNET3 virtual network adapter component of VMware ESX. A malicious actor with local administrative privileges on a guest virtual machine can exploit this flaw to escape the virtualized environment and execute arbitrary code on the ESXi host. The vulnerability is specific to the VMXNET3 adapter; other virtual network adapter types are not affected. This issue was reported via Pwn2Own and is addressed in various ESXi 8.0 and 9.x patch releases.

## Affected products

- VMware ESX / ESXi 8.0 before ESXi80U3k-25595708, 9.0.x.x before ESXi-9.0.2.0100-25595025, 9.1.x.x before ESXi-9.1.0.0200-25557999
- VMware Cloud Foundation 5.x, 9.0.x.x, 9.1.x.x
- VMware vSphere Foundation 9.0.x.x, 9.1.x.x
- VMware Telco Cloud Platform 5.0.x, 5.1.x

## Timeline

- 2026-07-29: advisory: Initial publication by Broadcom (VMSA-2026-0006)
- 2026-07-30: disclosed: NVD publication date

## References

- [https://support.broadcom.com/web/ecx/support-content-notification/-/external/content/SecurityAdvisories/0/38017](https://support.broadcom.com/web/ecx/support-content-notification/-/external/content/SecurityAdvisories/0/38017)

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