Bug 2516657 (CVE-2026-72289)

Summary:	CVE-2026-72289 kernel: KVM: arm64: vgic: Check the interrupt is still ours before migrating it
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	rhel-process-autobot, 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 KVM (Kernel-based Virtual Machine) arm64 vgic (Virtual Generic Interrupt Controller) component of the Linux kernel. During interrupt migration, the vgic_prune_ap_list() function temporarily drops and reacquires locks. If an interrupt is removed from the active processor list (ap_list) during this unlocked period, a subsequent check for interrupt affinity may still pass, leading to a double deletion of the interrupt from the list. This double free-like condition could potentially lead to system instability or denial of service.	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 2026-08-15 06:24:20 UTC

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

KVM: arm64: vgic: Check the interrupt is still ours before migrating it

vgic_prune_ap_list() drops both ap_list_lock and irq_lock while migrating
an interrupt to another vCPU. After reacquiring the locks it only checks
that the affinity is unchanged (target_vcpu == vgic_target_oracle(irq))
before moving the interrupt, which assumes that an interrupt whose affinity
is preserved is still queued on this vCPU's ap_list.

That assumption no longer holds if the interrupt is taken off the ap_list
while the locks are dropped. vgic_flush_pending_lpis() removes the
interrupt from the list and sets irq->vcpu to NULL, but leaves
enabled/pending/target_vcpu untouched. As the interrupt is still enabled
and pending, vgic_target_oracle() returns the same target_vcpu, so the
affinity check passes and list_del() is run a second time on an entry that
has already been removed.

Also check that the interrupt is still assigned to this vCPU
(irq->vcpu == vcpu) before moving it.

Comment 1 Keith Grant 2026-08-18 19:12:42 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081500-CVE-2026-72289-e85e@gregkh/T