drm/virtio: use the DMA API for resource backing on Xen
Summary
| CVE | CVE-2026-98156 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-25 11:17:47 UTC |
| Updated | 2026-09-25 15:18:07 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | Secondary | 7.8 | HIGH | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H |
| 3.1 | CNA | DECLARED | 7.8 | HIGH | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
HighPrivileges Required
LowUser Interaction
NoneScope
ChangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected a3b815f09bb846255c458c181b8a5b1cc66891b4 93c557e947ef0040004b1ac6a1c1265d79a957e1 git | Not specified |
| CNA | Linux | Linux | affected a3b815f09bb846255c458c181b8a5b1cc66891b4 455184dbe9652d01470d3c5cf5edd09a7a673a99 git | Not specified |
| CNA | Linux | Linux | affected a3b815f09bb846255c458c181b8a5b1cc66891b4 6a736d2f9d0c6e6217fe7532bc4c50ceca71db78 git | Not specified |
| CNA | Linux | Linux | affected 4.20 | Not specified |
| CNA | Linux | Linux | unaffected 4.20 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.53 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2.7 7.2.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.3-rc2 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/93c557e947ef0040004b1ac6a1c1265d79a957e1 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/455184dbe9652d01470d3c5cf5edd09a7a673a99 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/6a736d2f9d0c6e6217fe7532bc4c50ceca71db78 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.