Bug 2502606 (CVE-2026-64106)

Summary: CVE-2026-64106 kernel: KVM: arm64: vgic-its: Reject restored DTE with out-of-range num_eventid_bits
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Kernel-based Virtual Machine (KVM) for arm64 architecture, specifically within the virtual Generic Interrupt Controller (vgic-its) module. A local user in userspace can restore an Interrupt Translation Service (ITS) Device Table Entry (DTE) with a size field that specifies more EventID bits than the virtual ITS supports. This unchecked value can lead to an oversized scan of the ITS table, potentially causing system instability or a denial of service.
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Description OSIDB Bzimport 2026-07-19 17:08:36 UTC 
In the Linux kernel, the following vulnerability has been resolved:

KVM: arm64: vgic-its: Reject restored DTE with out-of-range num_eventid_bits

Userspace can restore an ITS Device Table Entry whose Size field encodes
more EventID bits than the virtual ITS supports.  The live MAPD path
rejects that state, but vgic_its_restore_dte() accepts it and stores the
out-of-range value in dev->num_eventid_bits.

Reject restored DTEs with num_eventid_bits > VITS_TYPER_IDBITS before
allocating the device.  This mirrors the MAPD check and prevents the
restored state from reaching vgic_its_restore_itt(), where the unchecked
value can be converted into an oversized scan_its_table() range.
Comment 1 TEJ RATHI 2026-07-20 08:27:05 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026071921-CVE-2026-64106-767b@gregkh/T