CVE Alert: CVE-2025-54091 – Microsoft – Windows 10 Version 1809
CVE-2025-54091
Integer overflow or wraparound in Windows Hyper-V allows an authorized attacker to elevate privileges locally.
AI Summary Analysis
Risk verdict
High risk of local privilege escalation via Hyper-V; exploitation is not observed in the wild based on SSVC/ADP data, but the total impact potential warrants prompt patching.
Why this matters
If exploited, an attacker could gain SYSTEM-level control on the host and compromise connected VMs, risking data integrity, availability, and confidentiality across the virtualised estate. The ability to escalate privileges locally may enable further lateral movement within a data centre or cloud-hosted Hyper‑V deployment, with potential to disrupt production.
Most likely attack path
Attacker requires local access and existing user privileges (PR:L) with no user interaction (UI:N). The flaw leverages a Hyper‑V memory/overflow condition to elevate privileges (CWE-190/122 with total impact), so exploitation would occur on the host or via a VM escape scenario. Initial access is not remote; success concentrates control on the affected host, enabling broader host-VM compromise if other trust boundaries exist.
Who is most exposed
Environments running Hyper‑V on Windows Server 2019/2022 and consumer/professional Windows builds with Hyper‑V enabled are most at risk, particularly data-centre hosts, cloud hypervisors, and organisations with legacy 1809/21H2 deployments still in use.
Detection ideas
- Privilege-escalation or unusual SYSTEM/hypervisor service activity in Windows Security logs.
- Unexplained Hyper‑V or virtualization-related process starts, crashes, or memory-corruption dumps.
- Anomalous guest-to-host interactions or hypervisor calls; unexpected memory/heap events.
- Indicators in monitoring tools of failed or blocked patch attempts; missing patch KBs.
Mitigation and prioritisation
- Apply the Microsoft security updates addressing CVE-2025-54091 to all affected builds.
- Verify patch deployment across Hyper‑V hosts and guest VMs; enforce patching in the next maintenance window.
- If patching is delayed, reduce exposure by minimising unnecessary Hyper‑V surface area, disabling unused guest-to-host pathways, and tightening admin/privilege access on hosts.
- Enable relevant security mitigations and monitor Hyper‑V and host integrity logs for escalation signals.
- Change-management: test patches in staging, communicate timelines, and resume normal operations after verification.
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