Bug 2535159 (CVE-2026-89931)

Summary:	CVE-2026-89931 kernel: KVM: nVMX: Ensure KVM_REQ_GET_NESTED_STATE_PAGES is cleared on VM-Exit
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Kernel-based Virtual Machine (KVM) nVMX component of the Linux kernel. This vulnerability arises from improper handling of nested virtual machine (VM) exits, where a specific request flag is not consistently cleared. This oversight can lead to the same memory pages being mapped twice, a form of memory corruption. A malicious guest virtual machine could exploit this to cause system instability, leading to a denial of service, or potentially gain unauthorized access to sensitive information.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-16 11:04:05 UTC

In the Linux kernel, the following vulnerability has been resolved:

KVM: nVMX: Ensure KVM_REQ_GET_NESTED_STATE_PAGES is cleared on VM-Exit

Always check and clear KVM_REQ_GET_NESTED_STATE_PAGES when emulating a
nested VM-Exit to ensure the request is cleared, even when KVM was built
with CONFIG_KVM_HYPERV=n, as KVM subtly relies on the "check" to clear
the flag and thus avoid double-mapping the vmcs12 pages, e.g. if KVM
manages to bail from VM-Enter without processing the request, and then
emulates VMLAUNCH or VMRESUME.

Comment 1 Keith Grant 2026-09-16 16:28:18 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89931.mbox