4 Mar 2025

VMware Security Alert: Hypervisor Vulnerabilities CVE-2025-22224, 22225, 22226 Explained

Demetrios S Mustakas Jr

Introduction

On March 4, 2025, Broadcom issued VMSA-2025-0004, disclosing actively exploited vulnerabilities in VMware ESXi, Workstation, and Fusion. CVE-2025-22224, CVE-2025-22225, and CVE-2025-22226 allow attackers to escape virtual machines, execute arbitrary code on the host, and exfiltrate sensitive data. These threats pose a critical risk to cloud and enterprise environments where VMware hypervisors are foundational. Organizations must act immediately to patch affected systems and prevent exploitation.

What is it?

VMware has disclosed three critical vulnerabilities affecting its hypervisor and desktop virtualization solutions. Each vulnerability targets a different component of the VMware architecture, but all have serious security implications.

CVE-2025-22224: VMCI Heap-Overflow Vulnerability

What it is: A heap-based buffer overflow in the Virtual Machine Communication Interface (VMCI), which allows an attacker inside a guest VM to execute arbitrary code as the VMX process on the ESXi host.

Exploit Scenario: A malicious actor with local administrative privileges inside a virtual machine can craft a specially designed payload that triggers a heap overflow, leading to privilege escalation on the hypervisor. This could allow attackers to break out of the VM sandbox and compromise the underlying ESXi host.

CVE-2025-22225: ESXi Arbitrary Write Vulnerability

What it is: An ESXi vulnerability allowing an attacker with VMX process-level access to modify kernel memory, potentially leading to hypervisor takeover.

Exploit Scenario: If an attacker gains access to the VMX process, they could leverage this vulnerability to execute malicious code in the ESXi kernel, bypassing isolation mechanisms and gaining host-level control. For an attacker to exploit CVE-2025-22225, they must first gain access to the VMX process. This could occur through privilege escalation inside a guest VM, exploitation of a separate VM escape vulnerability (such as CVE-2025-22224), or direct compromise of vSphere/vCenter. Once an attacker gains control over the VMX process, they can leverage this arbitrary write flaw to manipulate the ESXi kernel, potentially leading to a full hypervisor takeover.

CVE-2025-22226: HGFS Information Disclosure Vulnerability

What it is: An out-of-bounds read vulnerability in the Host-Guest File System (HGFS) that allows an attacker inside a VM to access sensitive memory data from the ESXi host.

Exploit Scenario: A compromised VM could read portions of memory that belong to the VMX process, leading to sensitive data leakage, which may include encryption keys, credentials, or system configurations. This could allow attackers to extract sensitive encryption keys or credentials stored in memory, potentially leading to further privilege escalation.

Why does it matter?

These vulnerabilities are particularly concerning because they enable VM escape, host compromise, and information disclosure, three of the most dangerous attack scenarios in virtualized environments.

Impact on VMware Platforms

VMware ESXi: If exploited, these vulnerabilities could compromise the entire hypervisor, allowing attackers to move laterally to other virtual machines running on the same host.

VMware Workstation & Fusion: Workstation and Fusion users running virtual machines on desktop environments may be at risk of privilege escalation and host compromise, potentially leading to wider network breaches.

VMware Cloud Foundation & Telco Cloud Platform: Any organization leveraging these platforms for large-scale virtualization deployments is at risk of multi-tenant compromise, which could expose sensitive workloads.

*Hypothetical - Impact on Nested Virtualization: In environments utilizing nested virtualization, an exploited guest VM could (conceivably) attempt to escape multiple virtualization layers, affecting both the ESXi host and any higher-level hypervisor managing it.

Implications for the Enterprise

Risk of Hypervisor Compromise: If a attacker gains control over the hypervisor, they can manipulate or disrupt entire virtual environments, leading to data breaches or ransomware attacks.

Escalation to Cloud and Hybrid Environments: Hybrid cloud environments increase the risk of attackers extending an on-prem ESXi breach into cloud-hosted VMware workloads. If an adversary exploits an ESXi vulnerability on-prem, they may leverage vSphere Linked Mode, SSO misconfigurations, vSphere Replication, or VMware HCX to pivot into AWS VMware Cloud, Azure VMware Solution, or other hybrid deployments. Additionally, compromised vSphere API credentials could allow attackers to manipulate workloads in the cloud, potentially leading to persistent compromise beyond the traditional data center, making remediation significantly harder.

Compliance and Regulatory Impact: A breach resulting from these vulnerabilities could violate security and compliance mandates, such as PCI-DSS, HIPAA, and GDPR, leading to fines, legal consequences, and reputational damage.

Threat Actor Perspective

These vulnerabilities appeal to ransomware groups and nation-state actors, as they enable hypervisor compromise, mass VM encryption, and long-term stealth persistence. The ESXiArgs ransomware campaign (2023-2024) demonstrated how attackers exploit unpatched ESXi hosts to encrypt entire virtual infrastructures, while nation-state actors have deployed custom VMware rootkits to establish long-term persistence. Given these trends, CVE-2025-22224, CVE-2025-22225, and CVE-2025-22226 are likely to be rapidly integrated into Metasploit, Cobalt Strike, and other attack frameworks, increasing the urgency for immediate remediation.

What can I do about it?

VMware has released patches to address these vulnerabilities. Since there are no available workarounds, immediate patching is required.

Identify Affected Systems

1. Review your VMware infrastructure to determine which versions of ESXi, Workstation, or Fusion are deployed.
2. Use VMware vSphere Client, vSphere Lifecycle Manager (vLCM), or PowerCLI to generate an inventory of affected hosts.

Apply Security Patches

1. Download the latest security updates from VMware’s official advisory page.
2. Apply patches in a controlled testing environment before deploying to production.
3. Fixed Versions:

ESXi:

1. ESXi 8.0 Update 2d (Build 24585300)
2. ESXi 7.0 Update 3l (Build 24585400)

Workstation:

1. Workstation 17.6.3

Fusion:

1. Fusion 13.6.3

Restart and Validate Patch Application

1. After applying patches, restart all affected hosts to ensure the updates take effect.
2. Validate that patches were successfully applied using ESXCLI commands:
3. esxcli software vib list | grep ESXi
4. Monitor system logs for any irregularities post-update.

Enhance Monitoring & Detection

1. Enable VMware Log Insight or forward vCenter logs to a SIEM (Splunk, Elastic, etc.) to detect suspicious activity.
2. Key logs to monitor:
3. /var/log/vmkernel.log
4. /var/log/vmkwarning.log
5. /var/log/vmware.log

Restrict Access to VMX Process

1. Implement Role-Based Access Control (RBAC) to restrict administrative access to virtual machines.
2. Disable unnecessary services, such as HGFS, if not required for your environment.

Review Virtual Machine Hardening Best Practices

1. Enforce VM Escape Mitigation Settings:
2. isolation.tools.hgfsServerSet.disable = "TRUE"
3. isolation.tools.hgfs.disable = "TRUE"
4. Limit exposed VM interfaces to reduce attack surface.

Incident Response Preparedness

1. Ensure your SOC (Security Operations Center) is aware of this advisory and has a playbook in place for detecting and responding to exploit attempts.

Conclusion: Bottom Line

The VMSA-2025-0004 advisory is a critical security concern for organizations running VMware ESXi, Workstation, and Fusion. With confirmed active exploitation, immediate remediation is required to prevent hypervisor compromise, data breaches, and system-wide disruptions.

VMware vulnerabilities have historically been prime targets for ransomware operators and APT groups. The ESXiArgs ransomware campaign demonstrated how unpatched hypervisors can be used as footholds for mass encryption attacks, while nation-state actors have deployed custom VMware rootkits to persist undetected inside virtual environments.

Given these trends, CVE-2025-22224, CVE-2025-22225, and CVE-2025-22226 will likely be rapidly integrated into Metasploit, Cobalt Strike, and other attack frameworks. Organizations must act immediately to patch affected systems, harden their VMware environments, and monitor for signs of exploitation, before these vulnerabilities become widespread tools for cyber adversaries.

References

VMSA-2025-0004: VMware ESXi, Workstation, and Fusion updates address multiple vulnerabilities (CVE-2025-22224, CVE-2025-22225, CVE-2025-22226)https://support.broadcom.com/web/ecx/support-content-notification/-/external/content/SecurityAdvisories/0/25390