VMware ESXi and Workstation TOCTOU Race Condition (CVE-2025-22224)

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-2025-22224 is a time-of-check time-of-use (TOCTOU) race condition (CWE-367) affecting VMware ESXi and Workstation. This flaw leads to an out-of-bounds write, which could allow an attacker to execute arbitrary code on the host system. Specifically, the execution occurs within the context of the VMX process associated with the virtual machine.

Exposure and applicability

This vulnerability is applicable to environments running VMware ESXi or VMware Workstation. The attack vector is restricted: a successful exploit requires the attacker to already possess local administrative privileges on a guest virtual machine. This represents a VM-escape scenario where an attacker moves from the guest environment to the host process.

On March 4, 2025, CISA added this vulnerability to the Known Exploited Vulnerabilities (KEV) catalog, indicating that it has been observed in active exploitation. For U.S. federal agencies, CISA has established a remediation deadline of March 25, 2025.

Remediation priorities

Our analysis suggests prioritizing assets based on the level of trust granted to guest VM administrators. Because this is a local-to-host escalation, VMs managed by third parties or those with high turnover of administrative access represent the highest risk.

1. Immediate Patching/Mitigation: Apply vendor-supplied updates or mitigations as specified in Broadcom’s security advisories. This is the primary method to address the underlying TOCTOU flaw.
2. Privilege Review: Audit guest VM administrative accounts. Reducing the number of users with local admin rights on guests limits the pool of potential attackers who can trigger this race condition.
3. Isolation Assessment: Evaluate the isolation between the VMX process and other critical host functions to determine if compensating controls can limit the impact of a successful escape.
4. Decommissioning: If mitigations are unavailable for specific legacy versions in use, discontinue use of the affected product version.

How to validate remediation

Verification must go beyond confirming a version number. While updating the software is the required action, defenders should verify that the mitigation is active and effective:

• Vendor Validation: Follow the specific verification steps provided by VMware/Broadcom to ensure the patch was applied correctly across all hosts in a cluster.
• Configuration Audit: If using compensating controls or configuration-based mitigations instead of a full patch, use configuration management tools to verify that the specific settings are enforced and have not been reverted.

Limits and open questions

It remains unknown whether this vulnerability is being utilized by known ransomware campaigns. Additionally, while patching addresses the race condition, it does not eliminate the inherent risk associated with granting administrative privileges to guest VMs. Residual risk persists if attackers find alternative paths to achieve local admin status on a guest VM to trigger similar out-of-bounds write conditions.

Source and editorial note

CVE-2025-22224: VMware ESXi and Workstation TOCTOU Race Condition 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 22, 2026 at 01:06 UTC.

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