CVE-2025-22226: VMware ESXi, Workstation, and Fusion Information Disclosure Vulnerability

CVE-2025-22226 is an information disclosure vulnerability affecting VMware ESXi, Workstation, and Fusion. It stems from an out-of-bounds read in the HGFS component and can let an attacker who already holds administrative privileges inside a virtual machine leak memory from the host-side vmx process. For organizations running VMware virtualization stacks, this matters because memory disclosure can expose sensitive host or hypervisor data that should remain isolated from guest workloads, potentially aiding further compromise of the virtualization layer.

Defenders should treat this as a guest-to-host information leak that requires administrative access on the guest. Specifics such as exact affected builds and fixed versions must be confirmed against the vendor advisory.

How it works

The weakness is classified as CWE-125, an out-of-bounds read. In this case the flaw exists in HGFS (the Host-Guest File System functionality used for shared folders and related guest-host interactions). An attacker who has already obtained administrative privileges inside a virtual machine can trigger the out-of-bounds read condition. Successful exploitation results in leakage of memory contents belonging to the vmx process that runs on the host or hypervisor side.

Because the attacker starts with admin rights on the guest, the vulnerability does not itself provide initial access; it allows escalation of information access across the guest-host boundary. No public details on precise trigger sequences or memory regions are provided here; treat any exploit claims as unconfirmed until verified against the vendor advisory and your own testing.

Am I affected? How to find it in your systems

VMware ESXi is commonly deployed as the bare-metal hypervisor in data centers and private clouds. VMware Workstation and Fusion are desktop hypervisors used by developers, testers, and IT staff on Windows, Linux, and macOS endpoints. Inventory all systems running any of these products.

• Query configuration management databases, asset inventories, and hypervisor management consoles (vCenter, standalone ESXi hosts, desktop management tools) for ESXi, Workstation, and Fusion installations.
• On ESXi hosts, use esxcli or the vSphere Client to list installed versions and enabled features related to HGFS or VMware Tools shared folders.
• On Workstation and Fusion clients, check the product version via the About dialog or package managers and note whether shared-folder or HGFS-related features are enabled.
• Confirm the precise build numbers against the vendor advisory; public detail on exact vulnerable ranges is limited to the product names listed.

Telemetry signs of exploitation are not detailed in available summaries. Monitor for anomalous memory-access patterns or unexpected HGFS activity originating from guests that hold administrative privileges, and review host logs for unusual vmx process behavior. Correlate with guest admin activity logs.

How to remediate

Apply the vendor-supplied update for ESXi, Workstation, and Fusion as the primary remediation. Follow the mitigations and patch instructions published in the official VMware advisory for CVE-2025-22226. CISA guidance directs organizations to apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

• Schedule and deploy the fixed builds through your normal change-control process, prioritizing internet-facing or multi-tenant ESXi hosts.
• After patching, verify the new version is running and that HGFS-related services behave as expected.
• As a general hardening step for this class of guest-to-host issues, restrict administrative privileges inside virtual machines to only those accounts that require them, and disable unnecessary HGFS or shared-folder features where operationally feasible.

If you can't patch immediately

Until the vendor update can be applied, reduce exposure with compensating controls focused on limiting the attacker's starting privileges and containing potential leaks.

• Segment virtualization hosts and management networks so that compromised guests cannot easily reach other critical systems.
• Disable or tightly control HGFS and shared-folder functionality on hosts and guests that do not require it.
• Enforce least-privilege administrative access inside all virtual machines; remove or tightly audit local admin rights.
• Increase monitoring of vmx process behavior, guest-to-host file-system interactions, and any anomalous memory or process activity on the hypervisor.
• Where available, apply virtual patching or host-based controls that restrict the HGFS attack surface, confirming effectiveness against the vendor advisory.

These measures lower risk but do not eliminate the underlying out-of-bounds read; plan to patch as soon as possible.

If your data may have been exposed

Actively exploited vulnerabilities of this type can contribute to broader breaches even when ransomware use is not documented for the specific CVE. If you suspect memory leakage or subsequent host compromise, treat the incident as a potential data exposure event: isolate affected hosts, preserve forensic evidence, and follow your incident-response playbook. You can run a free exposure scan of your email addresses to check whether associated credentials or personal data already appear in known breach datasets.