Bug 2461467 (CVE-2026-31558)

Summary:	CVE-2026-31558 kernel: LoongArch: KVM: Make kvm_get_vcpu_by_cpuid() more robust
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	unspecified	CC:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in the Linux kernel's Kernel-based Virtual Machine (KVM) component. A local attacker could potentially trigger an out-of-bounds memory access by providing a negative 'cpuid' parameter to the 'kvm_get_vcpu_by_cpuid()' function. This could lead to system instability or potentially other impacts due to memory corruption.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-04-24 15:03:08 UTC

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

LoongArch: KVM: Make kvm_get_vcpu_by_cpuid() more robust

kvm_get_vcpu_by_cpuid() takes a cpuid parameter whose type is int, so
cpuid can be negative. Let kvm_get_vcpu_by_cpuid() return NULL for this
case so as to make it more robust.

This fix an out-of-bounds access to kvm_arch::phyid_map::phys_map[].

Comment 1 Keith Grant 2026-04-24 17:29:58 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026042457-CVE-2026-31558-1140@gregkh/T