Historical catalog analysis: CISA added this entry on March 04, 2025. The entry reflects catalog information retrieved on August 31, 2026, not a snapshot archived on the inclusion date. Check current vendor guidance before acting.
What the vulnerability is
CVE-2025-22226 is an information disclosure vulnerability affecting VMware ESXi, Workstation, and Fusion. The flaw stems from an out-of-bounds read (CWE-125) within the Host Guest File System (HGFS). If successfully exploited, an attacker who has already obtained administrative privileges on a virtual machine could leak memory from the vmx process.
Exposure and applicability
This vulnerability is particularly relevant to healthcare organizations utilizing on-premises virtualization to host electronic Protected Health Information (ePHI) or critical clinical workloads. Because VMware ESXi serves as a foundational hypervisor for many health system data centers, a flaw that threatens the isolation between the guest virtual machine and the underlying process could potentially expose sensitive data residing in memory.
CISA added this vulnerability to its Known Exploited Vulnerabilities (KEV) catalog on March 4, 2025, indicating that it has been observed in active exploitation. While CISA has set a remediation deadline of March 25, 2025, for federal agencies, this date serves as a risk indicator for private healthcare providers rather than a legal mandate.
Remediation priorities
Based on the reported vulnerability and its inclusion in the KEV catalog, we suggest the following prioritized actions for healthcare security leaders:
- Apply Vendor Updates: The primary defense is to apply mitigations or patches according to official VMware/Broadcom instructions. This addresses the root cause of the out-of-bounds read.
- Review Guest VM Administrative Access: Since exploitation requires administrative privileges within a virtual machine, organizations should audit who has high-level access to VMs hosting sensitive clinical data. Reducing the number of administrative accounts could reduce the likelihood of an internal or compromised account being used to trigger the leak.
- Evaluate HGFS Usage: Organizations should determine if HGFS is necessary for their current clinical workflows. Disabling unnecessary features that facilitate host-guest interaction may limit the attack surface.
How to validate remediation
To verify that exposure has been reduced, virtualization administrators should:
* Verify Versioning: Confirm that all ESXi hosts, Workstation, and Fusion instances are running versions that incorporate the vendor’s fix for CVE-2025-22226.
* Audit Configuration: Review the configuration of virtual machines to ensure that HGFS is only enabled where strictly required for operational continuity.
Note: A version check confirms a patch was applied but does not guarantee immunity from all potential hypervisor threats.
Limits and open questions
It remains unknown whether this vulnerability has been utilized specifically by ransomware actors. Additionally, while the entry path requires administrative access to a VM, it is not specified how an attacker would initially gain those privileges in a healthcare environment.
Applying these mitigations could reduce the likelihood of memory leakage but does not eliminate all risks associated with virtualization. Residual risk remains if attackers find alternative paths to escalate privileges or bypass hypervisor isolation.
Source and editorial note
CVE-2025-22226: VMware ESXi, Workstation, and Fusion Information Disclosure Vulnerability · Source date: March 04, 2025 · Retrieved August 31, 2026.
Material facts are tied to the cited primary source. Recommendations are independent defensive analysis unless attributed to the source. Confirm consequential decisions against current authoritative guidance.
Archive date: March 07, 2025. The displayed post date is assigned three days after the source date to organize this retrospective archive; it does not mean this site published the analysis then. First published by this site: October 19, 2026 at 01:03 UTC.
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