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CVE-2026-46059: KVM: nSVM: Always use NextRIP as vmcb02's NextRIP after first L2 VMRUN

mediumCVSS 5.5CVE-2026-46059

CSIRTS triage

product: Linux kernel (KVM hypervisor)Misconfiguration
What
KVM's nested virtualization (nSVM) incorrectly uses NextRIP without proper validation when returning from L2 guest VMRUN, potentially causing guest state corruption.
Who is affected
Hypervisors running nested virtual machines using AMD-based KVM with nSVM support.
Urgency
Medium; CVSS 5.5 with guest-to-host escape potential depending on implementation details.
Action
Update to a patched Linux kernel version that always validates and properly sets NextRIP in vmcb02 after first L2 VMRUN.

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

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Details

Source
Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity
medium — CVSS 5.5
Published
2026-08-06
Exploitation
Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-46059

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.

Referenced CVEs

CVECSIRTS overviewExternal
CVE-2026-46059coverage & exploitation statusNVD · CVE.org

Same CVEs, other sources

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

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