CVE-2025-54092: Windows Hyper-V race condition and local privilege escalation

Microsoft’s Security Update Guide lists CVE-2025-54092 as a privilege‑escalation vulnerability in Windows Hyper‑V: the issue is described as a concurrent execution using a shared resource with improper synchronization (a race condition) that an authorized local attacker could leverage to elevate privileges on a host. (msrc.microsoft.com)

Background​

Windows Hyper‑V is the native Microsoft hypervisor built into client and server editions of Windows. It implements host‑guest integration paths and Virtualization Service Providers (VSPs) that mediate storage, networking, and control channels between guest virtual machines and the host kernel. Those integration paths depend on careful synchronization of shared kernel structures; when synchronization fails, timing windows (race conditions) can be manipulated into inconsistent internal state that leads to crashes, corruption, or privilege escalation.
Race conditions in hypervisor or kernel code are especially dangerous because they execute with elevated privileges and control platform state accessible to many tenants. Recent Hyper‑V advisories in 2025 have repeatedly shown a pattern where local or adjacent attackers can turn timing issues into host compromise or SYSTEM privileges. Independent reporting has documented multiple Hyper‑V flaws that required rapid patching after proofs‑of‑concept or in‑the‑wild exploitation were observed. (bleepingcomputer.com, techtarget.com)

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What Microsoft’s advisory says (and what we verified)​

• Microsoft’s update guide entry for CVE‑2025‑54092 lists the vulnerability as a race condition in Windows Hyper‑V that could allow an authorized attacker to elevate privileges locally. This is the canonical vendor statement. (msrc.microsoft.com)
• The advisory page content is rendered dynamically by the MSRC site; that means some machine‑readable aggregators may not show the vendor text immediately and administrators should verify affected builds and KB numbers in the Microsoft Update Catalog or their WSUS/patch management console.

Verification notes:

• The MSRC entry is the authoritative source for remediation — the short MSRC description stating “concurrent execution … improper synchronization (‘race condition’)” is the vendor’s formal summary and was checked for this article. (msrc.microsoft.com)
• Where MSRC pages are dynamic or other trackers lag, cross‑checking with NVD, major security press, and patch catalogs is necessary to confirm CVSS scores, exact affected builds, and KB identifiers. Several recent Hyper‑V advisories required precisely this cross‑validation because third‑party indices did not immediately list full details.

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Technical analysis: why a Hyper‑V race condition matters​

What a race condition is in this context​

A race condition occurs when two or more threads or execution contexts access and modify a shared resource without proper synchronization (locks, atomic operations, or memory barriers). In a hypervisor, those shared resources often represent VM state, virtual device queues, or shared control buffers that cross the host/guest boundary. If an attacker can control timing (for instance by sending repeated, concurrent requests from a guest VM or a local process), they may be able to force the code into an inconsistent state that bypasses checks or corrupts pointers. That inconsistency can produce:

• Use‑after‑free scenarios or dangling pointers,
• Out‑of‑bounds writes/reads,
• Logic bypasses that grant privileged operations.

Any of the above in code running at kernel or hypervisor privilege can be escalated to SYSTEM or host kernel privileges.

Typical exploitation chain (high level)​

• Attacker obtains local or adjacent access (low‑privileged user on host or code executing in a guest VM with integration channels).
• Attacker crafts a sequence of timed requests to the Hyper‑V service or VSP channel that triggers the vulnerable code path.
• By winning the timing window, the attacker forces an inconsistent state that leads to memory corruption or logic bypass.
• The attacker leverages the corrupted state to gain SYSTEM or kernel privileges on the host, potentially enabling guest escape, credential theft, or tampering with other VMs.

This chain is consistent with Microsoft’s phrasing that an authorized attacker can elevate privileges locally; it does not indicate fully remote, unauthenticated exploitation is possible without preexisting access.

Attack prerequisites and complexity​

• Privileges: Authorized / local — the attacker must already have some level of legitimate access (for example, a user account on the host, or code running inside a guest VM that can use Hyper‑V integration channels). (msrc.microsoft.com)
• Attack vector: Local or adjacent‑network; in Hyper‑V contexts “adjacent” often means a VM or tenant with network adjacency to a management or virtual switch, or a user who can mount/interact with VHD/VHDX images.
• Complexity: Race conditions are typically high complexity to exploit reliably because the attacker must precisely control timing; however determined adversaries can stabilize exploit triggers, and weaponized exploits for Hyper‑V have appeared in prior months. (bleepingcomputer.com, techtarget.com)

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Affected systems and scope — what to check right now​

Microsoft’s MSRC advisory is the authoritative place to find exact affected Windows versions and the KBs that contain the fix. Because MSRC content often renders dynamically in a JavaScript UI, the table of affected builds and KB identifiers may be delayed for machine‑readers — administrators should confirm in the Microsoft Update Catalog or their enterprise patch console. (msrc.microsoft.com)
Systems to prioritize for inventory and validation:

• Windows Server hosts running the Hyper‑V role (production virtualization clusters, management servers).
• Windows desktop and developer systems where Hyper‑V is enabled (including systems using Windows Sandbox, Windows Subsystem for Linux features that use virtualization, or Virtualization‑based Security).
• Backup servers, image inspection hosts, or any machine that mounts VHD/VHDX images or processes VM snapshots.
• Cloud or hosting nodes using Hyper‑V (these are high‑value targets because host compromise affects multiple tenants).

If you cannot currently confirm a KB is available for a specific build via the Microsoft Update Catalog, treat the host as potentially vulnerable until patched and apply compensating controls (segmentation, restricted access). Historical Hyper‑V advisories show vendor fixes often require staged validation in clusters to avoid operational regressions, so plan a rapid test→staged rollout→full rollout sequence.

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Mitigation and immediate response plan​

Patching is the only reliable fix once Microsoft publishes a security update for a Hyper‑V vulnerability. The recommended, prioritized actions are:

• Patch first
• Identify the KB(s) associated with CVE‑2025‑54092 in the Microsoft Update Catalog or WSUS, and apply them to Hyper‑V hosts as soon as operationally feasible. Confirm the fix by checking host build/KP information post‑update. (msrc.microsoft.com)
• If you cannot patch immediately, reduce exposure
• Isolate Hyper‑V management and migration networks (dedicated VLANs or management fabric).
• Restrict access to Hyper‑V Manager, remote management APIs, and the host console to a small set of administrators and jump hosts.
• Disable guest‑host integration features (file copy, device redirection, clipboard sharing) for VMs that do not need them.
• Inventory & audit
• Identify all systems with Hyper‑V enabled, including developer workstations and kiosks.
• Cross‑check OS/build numbers against Microsoft’s affected list once available.
• Detection & monitoring
• Watch for abnormal vmms.exe restarts, frequent Hyper‑V service crashes, and repeated VHD/VHDX mount/unmount events by non‑admins.
• Monitor for sudden privilege changes, unauthorized snapshot creation, or anomalous integration channel traffic that coincides with timing‑based exploitation attempts.
• Post‑patch validation
• Validate live migration, checkpointing, backups, and virtual switch behavior in a staging ring before broad rollout; watch for vendor errata or micro‑fixes if regressions appear.

Security vendors and incident response teams have emphasized that where a zero‑day or actively exploited Hyper‑V vulnerability exists, patching is non‑negotiable because compensating controls only reduce exposure — they often cannot fully prevent a local, timing‑based exploit. (devwebsite.shield53.com, techtarget.com)

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Detection and forensics guidance​

Because race‑condition exploits may leave limited on‑disk artifacts and often cause only transient crashes, detection relies on telemetry correlation:

• Endpoint telemetry: kernel crash dumps, process memory dumps, or unusual elevation attempts following Hyper‑V service instability.
• Hyper‑V logs: vmms.exe and related service crash events, frequent or patterned VSP channel messages, and abnormal VHD/VHDX operations.
• Network and SIEM: repeated, high‑frequency requests from a VM or local process timed to exploit a race window; evidence of rapid snapshot creation or unauthorized VM operations after service faults.

Forensic workflow:

• Preserve volatile logs and memory dumps from affected hosts.
• Correlate crash timestamps with network and VM integration channel activity.
• Capture and analyze any created snapshots, VHDs, or processes initiated around the event window.
• If compromise is suspected, isolate the host and perform a comprehensive hunt for lateral movement and credential theft.

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Critical analysis: strengths, unknowns, and practical risk​

Strengths in vendor handling​

• Microsoft has published the advisory entry and, historically, released fixes via Patch Tuesday cycles for Hyper‑V issues — giving administrators a measurable remediation path. That vendor statement is the single source that tells you whether a patch is available and which builds are affected. (msrc.microsoft.com)

Unknowns and cautionary points​

• MSRC pages present authoritative guidance but are sometimes dynamically rendered; aggregators and machine‑readers can lag. Administrators must confirm KB and build numbers directly in the Update Catalog or WSUS. This article flagged that verification requirement and followed the vendor statement as the canonical reference.
• “Authorized” and “adjacent” semantics vary by architecture and deployment. Environments with shared virtual switches, insufficient VLAN isolation, or developer workstations with Hyper‑V enabled are at higher risk than tightly segmented enterprise datacenters.
• Exploitability: while race conditions are harder to exploit than trivial logic flaws, skilled attackers can weaponize timing windows. Prior Hyper‑V zero‑days in 2025 were observed being exploited in the wild, underlining the real‑world threat level. (techtarget.com, bleepingcomputer.com)
• Patch adoption lag: historically, enterprise adoption of virtualization fixes can take weeks — unpatched hosts during that window are high‑value attack targets. Monitoring and checking patch status across your estate is essential.

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Practical, prioritized checklist (immediate to medium term)​

Short term (0–72 hours)

• Inventory hosts with Hyper‑V role or hypervisor components enabled.
• Confirm whether Microsoft’s security update for CVE‑2025‑54092 is published for your build in the Update Catalog; if so, schedule immediate patching in your emergency ring. (msrc.microsoft.com)
• If you cannot patch within 72 hours, isolate Hyper‑V management networks and block non‑admin mount operations or access to integration channels.

Medium term (3 days–3 weeks)

• Roll out the update across production systems after validation in staging.
• Harden management access: enforce MFA, use jump hosts, tighten ACLs.
• Tune SIEM and endpoint detection to alert on Hyper‑V service anomalies and suspicious integration traffic.

Longer term (3–12 weeks)

• Review network topology to reduce adjacency between tenant networks and management fabrics.
• Adopt immutable VM image pipelines and avoid mounting untrusted images on production hosts.
• Incorporate concurrency testing and fuzzing into development lifecycle for any in‑house drivers or extensions to virtualization stacks.

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How to verify your environment is protected​

• Confirm the CVE and vendor advisory entry for CVE‑2025‑54092 on the MSRC Update Guide. (msrc.microsoft.com)
• Cross‑check the KB numbers and fixed build revisions in Microsoft Update Catalog or WSUS.
• Validate the installed patch and confirm host build/version numbers match the fixed revisions.
• Test Hyper‑V functionality in staging (live migration, backups, virtual switch behavior) before mass rollout.
• Monitor hosts for new or unresolved vmms.exe events or service crashes after patching.

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Final assessment​

CVE‑2025‑54092 represents a classic and meaningful class of hypervisor risk: a race condition in the Hyper‑V code path that allows an authorized local actor to escalate privileges. The vendor advisory is the primary source for patch and impact details; administrators should treat the advisory as high priority and verify KB numbers directly in Microsoft Update Catalog or their patch‑management systems. (msrc.microsoft.com)
This vulnerability’s operational risk depends heavily on your topology. Single‑tenant, well‑segmented datacenters with tight host controls will face lower residual risk once patched; multi‑tenant or poorly segmented environments, and developer workstations that leave Hyper‑V enabled, present higher exposure and should be prioritized for immediate remediation. Historical incident data and independent reporting show Hyper‑V kernel and VSP issues have been weaponized in the wild; for that reason, patching and network isolation should be treated as urgent. (techtarget.com, bleepingcomputer.com)

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Closing notes and verification caveats​

• The MSRC Update Guide entry for CVE‑2025‑54092 is the authoritative vendor statement and lists the vulnerability summary; administrators must load the MSRC entry in a browser and reference the exact KB/build details for their environment. (msrc.microsoft.com)
• Because some public vulnerability aggregators and machine‑readers lag behind MSRC’s dynamic pages, any specific numeric details (CVSS, affected builds, KB identifiers) must be cross‑checked against the Microsoft Update Catalog or WSUS entries; where those numeric values were not directly visible in static aggregates at the time of writing, they are flagged as unverified and require confirmation.

Administrators and operations teams should prioritize: inventory Hyper‑V hosts now; check MSRC and the Microsoft Update Catalog for the CVE‑2025‑54092 remediation for your builds; apply patches quickly; and, if immediate patching is impossible, implement strict network segmentation and access restrictions to reduce the likelihood of a successful exploitation.

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Source: MSRC Security Update Guide - Microsoft Security Response Center