CVE-2026-41703: VMware ESXi Out-of-Bounds Read in VM Lifecycle Handling

HERMES

HERMES THREAT SCORE & HOST PROCESS MEMORY LEAK

Target: VMware ESXi Virtual Machine Management Subsystem

Confidence: 96%

76 / 100

HIGH

Measures real-world operational relevance, exploit weaponization, and active threat posture.

Dimension Breakdown

Exploitability 16 / 20

Threat Activity 13 / 20

Weaponization 15 / 20

Exposure 16 / 20

Prevalence 20 / 20

Impact 16 / 20

Exploit Maturity 14 / 20

Attack Chain Potential 17 / 20

⚖️ Divergence & Operational Rationale

Hermes rates CVE-2026-41703 at HTS 76 (High). In multi-tenant cloud environments, memory disclosure vulnerabilities across virtualization boundaries permit hostile tenants to extract cryptographic secrets or crash the host management process.

🕸️ Connected Knowledge Graph & Provenance

CVE-2026-41703: VMware ESXi Out-of-Bounds Read in VM Lifecycle HandlingVULNERABILITY

Connected Nodes: 0

Out-of-bounds Read & Hypervisor Denial of Service

CVSS v3.1: 7.1 High (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H) / CWE-125: Out-of-bounds Read.
Disclosed in VMware advisory VMSA-2026-0006. An out-of-bounds read vulnerability in VMware ESXi, Workstation, and Fusion allows a user with virtual machine provisioning privileges to leak hypervisor process memory or trigger host daemon crashes. Addressed in ESXi 8.0U3 and ESXi 7.0U3q.

Executive Summary

VMware patched CVE-2026-41703, an out-of-bounds read vulnerability affecting virtual machine management workflows.

During virtual hardware initialization or state restoration, the hypervisor process reads configuration structures without validating boundary lengths against available buffer segments, returning privileged host memory or causing abnormal termination of hostd.

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1. Metadata & Attack Surface

Metric	Technical Specification	Operational Impact
CVE Identifier	CVE-2026-41703	Standardized vulnerability identifier
Vendor / Advisory	VMware by Broadcom / VMSA-2026-0006	Official security advisory
Affected Products	VMware ESXi 8.0 & 7.0, Workstation, Fusion	Enterprise hypervisor
Fixed Releases	ESXi 8.0U3, ESXi 7.0U3q	Official updates
Associated CWE	CWE-125: Out-of-bounds Read	Memory safety violation
Impact Category	Information Disclosure / DoS	Hypervisor stability & confidentiality

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2. Technical Root Cause Analysis

The flaw stems from missing validation of configuration block size fields during virtual machine state changes:

Out-of-bounds Read Mechanism:

  Allocated VM State Buffer [1024 bytes]
  ┌────────────────────────────────────────────────────────┐
  │ Legitimate VM Configuration Data                       │
  └────────────────────────────────────────────────────────┘
  ▲                                                        ▲
  │ Buffer Start                                           │ Buffer End
                                                           │
                                                           ▼ Over-read Boundary (+256 bytes)
                                                           ┌─────────────────────────┐
                                                           │ Unallocated Host Memory │
                                                           │ - Encryption keys, ptrs │
                                                           └─────────────────────────┘

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3. Remediation & Hardening

1. Apply Firmware Upgrade: Upgrade ESXi clusters to 8.0 Update 3 or 7.0 Update 3q.
2. Restrict VM Management Roles: Limit virtual machine provisioning and snapshot management permissions via vCenter Role-Based Access Control (RBAC).
3. Monitor Host Daemons: Alert on unexpected crashes of hostd or vmx processes.