VMware Workstation and Fusion: Integer overflow in VMXNET3 virtual network adapter
Summary
VMware Workstation and Fusion versions 25H2 and 26H1 contain an integer overflow in the VMXNET3 virtual network adapter. A malicious actor with local administrative rights inside a virtual machine can exploit it to execute code on the host. The attack requires guest administrator access, so there is no direct remote path, but a compromised or untrusted guest VM can affect the host operating system and other VMs on it. A public proof of concept has been reported, while the reported capabilities differ between sources.
Affected
- VMware Workstation: 25H2, 26H1
- VMware Fusion: 25H2, 26H1
Fixed in
- VMware Workstation 26H1u1
- VMware Fusion 26H1u1
Workaround
- Broadcom's advisory VMSA-2026-0007 states that no workaround is available.
- A reported switch of guest network adapters from VMXNET3 to E1000 or E1000e has not been confirmed by Broadcom and is not a supported fix.
Exploitation
- A public proof of concept has been reported. Sources differ on whether it causes a host crash only or achieves code execution.
- No in-the-wild exploitation is known.
- CISA SSVC assessment: exploitation none, not automatable.
Our recommendation
- Update all VMware Workstation and Fusion installations on 25H2 or 26H1 to 26H1u1 as a priority.
- Inventory hosts and VMs that use the VMXNET3 adapter.
- Restrict guest administrator rights and do not run untrusted or downloaded VM images on unpatched hosts.
- Monitor for unexpected crashes of vmware-vmx processes and for suspicious activity on hosts.
Public exploits
Links to third-party sites, not checked by us – exploit code can contain malware. Only use it in isolated test environments.
- Proof of concept on GitHub (1 repositories)
0xCyberstan/CVE-2026-59346-POC
Research sources
- Broadcom advisory VMSA-2026-0007 support.broadcom.com
- SentinelOne CVE-2026-59346 www.sentinelone.com
- SQ Magazine: VMXNET3 flaw PoC sqmagazine.co.uk
- Security Affairs: Broadcom patches VMware Workstation and Fusion securityaffairs.com
- Hol.org CVE-2026-59346 hol.org
- FYI Solutions: VM escape CVE-2026-59346 fyisolutions.com
- Strix CVE-2026-59346 www.strix.ai
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 31 Oct 2026, 03:10.
Original description (NVD)
VMware Workstation and Fusion contain an integer-overflow vulnerability. 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. Affected versions: - VMware Workstation: 25H2, 26H1 (fixed in 26H1u1) - VMware Fusion: 25H2, 26H1 (fixed in 26H1u1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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