CVE-2026-64287: KVM: arm64: Bound used_lrs when flushing the pKVM hyp vCPU

mediumCVSS 6.1CVE-2026-64287

CSIRTS triage

Other

What: The vulnerability involves bounding used_lrs when flushing the pKVM hyp vCPU in KVM for arm64.
Who is affected: Deployments using KVM on arm64 architecture are affected.
Urgency: Remediation is necessary to prevent potential issues with vCPU flushing.
Action: Implement the fix to bound used_lrs when flushing the pKVM hyp vCPU.

AI-assisted analysis generated from the source advisory — verify against the original.

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 6.1
Published: 2026-07-14
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64287

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-642870.17% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 7% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-64287	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for KVM

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

unknownCVE-2022-4994: In the Linux kernel, the following vulnerability has been resolved: KVM: x86: wean fast IN from…nvd · 2026-07-30
unknownUSN-8617-1: Linux kernel (KVM) vulnerabilitiesubuntu · 2026-07-28
highCVE-2026-64555: In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: nv: Fix SPSR_E…nvd · 2026-07-27
unknownCVE-2026-64513: In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Unconditionally …nvd · 2026-07-25
unknownCVE-2026-64310: In the Linux kernel, the following vulnerability has been resolved: crypto: ccp - Do not initi…nvd · 2026-07-25
unknownCVE-2026-64288: In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: nv: Avoid dere…nvd · 2026-07-25