CVE-2026-63800: pNFS: Fix use-after-free in pnfs_update_layout()

criticalCVSS 9.8CVE-2026-63800

CSIRTS triage

vendor: KVM product: KVMOther

What: The vulnerability fixes a use-after-free issue in the pnfs_update_layout() function.
Who is affected: Deployments of KVM that utilize pNFS functionalities.
Urgency: Remediation is necessary to prevent potential crashes or security issues.
Action: Update to the latest version of KVM.

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: critical — CVSS 9.8
Published: 2026-07-14
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-63800

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-2026-638000.50% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 40% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-63800	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 pNFS

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.

criticalCVE-2026-63800: In the Linux kernel, the following vulnerability has been resolved: pNFS: Fix use-after-free i…nvd · 2026-07-19