Bug 2554837 (CVE-2026-98470)

Summary:	CVE-2026-98470 kernel: KVM: arm64: Don't WARN on an unknown VM ioctl in protected mode
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 Linux kernel's KVM (Kernel-based Virtual Machine) subsystem for ARM64. This vulnerability allows a local attacker to cause a Denial of Service (DoS). When running in protected mode, the kernel issues an internal warning upon receiving an unknown virtual machine I/O control (IOCTL) command from userspace. On hosts configured to panic on kernel warnings, this causes the host operating system to crash.	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 2026-10-18 15:22:03 UTC

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

KVM: arm64: Don't WARN on an unknown VM ioctl in protected mode

kvm_pkvm_ioctl_allowed() WARNs when kvm_get_cap_for_kvm_ioctl() doesn't
find the ioctl number in vm_ioctl_caps[], and kvm_arch_vm_ioctl() calls
it for every number the generic code doesn't handle, so
ioctl(vm_fd, 0xdeadbeef) from userspace taints a pKVM host and panics it
under panic_on_warn. The lookup is fed userspace input: return false,
and userspace gets the -EINVAL kvm_arch_vm_ioctl() returns for that
number on a host without pKVM.

Comment 1 Mauro Matteo Cascella 2026-10-20 08:38:49 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98470.mbox