Exposure of System Data to an Unauthorized Control Sphere Affecting kernel-64k-core package, versions *


Severity

Recommended
medium

Based on CentOS security rating.

Threat Intelligence

EPSS
0.13% (3rd percentile)

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  • Snyk IDSNYK-CENTOS10-KERNEL64KCORE-20216628
  • published29 Sept 2026
  • disclosed25 Sept 2026

Introduced: 25 Sep 2026

NewCVE-2026-98156  (opens in a new tab)
CWE-497  (opens in a new tab)

How to fix?

There is no fixed version for Centos:10 kernel-64k-core.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-64k-core package and not the kernel-64k-core package as distributed by Centos. See How to fix? for Centos:10 relevant fixed versions and status.

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

drm/virtio: use the DMA API for resource backing on Xen

On a Xen PV domain page addresses bear no relation to the real machine addresses the host would have to use to reach it. virtio_ring.c handles this correctly, vring_use_map_api() returns true for any xen_domain() regardless of VIRTIO_F_ACCESS_PLATFORM.

virtio-gpu makes the same decision independently, but its copy looks only at the feature bit:

bool use_dma_api = !virtio_has_dma_quirk(vgdev->vdev);

QEMU does not set iommu_platform on virtio-vga by default, so VIRTIO_F_ACCESS_PLATFORM is not negotiated, use_dma_api is false, and virtio_gpu_object_shmem_init() describes the framebuffer's backing pages to the host with sg_phys(). Those are guest-physical addresses. In a PV domain they resolve, on the host side, to pages belonging to some other domain, so the host scans out unrelated memory.

Move the decision into virtio_gpu_use_dma_api() and give it the xen_domain() check, like vring_use_map_api() has. This additionally enables the dma_sync_sgtable_for_device() calls in virtgpu_vq.c, which are required for correctness whenever swiotlb is in play.

Reproduced with a Xen 4.21 PV dom0 nested inside QEMU 8.2 with virtio-vga, on both a distro 6.8 kernel and 6.18 LTS. A PVH dom0 works fine and doesn't need this fix because it is identity-mapped, only PV dom0s are affected.

CVSS Base Scores

version 3.1