{"id":"CVE-2026-98156","title":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/virtio: use the DMA API for resource backing on Xen\n\nOn a Xen PV domain page addresses bear no relation to the real machine\naddresses the host would have to use to …","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/virtio: use the DMA API for resource backing on Xen\n\nOn a Xen PV domain page addresses bear no relation to the real machine\naddresses the host would have to use to …","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H","cwe":["CWE-497"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 4.20, < 6.18.53","linux_kernel >= 6.19, < 7.2.7","linux_kernel = 7.3"],"patched":["linux_kernel 7.2.7"],"published":"2026-09-25","updated":"2026-10-14","sourceUpdated":"2026-10-14T17:23:44.937","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-98156","references":[{"url":"https://git.kernel.org/stable/c/455184dbe9652d01470d3c5cf5edd09a7a673a99","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6a736d2f9d0c6e6217fe7532bc4c50ceca71db78","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/93c557e947ef0040004b1ac6a1c1265d79a957e1","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98156.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-98156"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2541329"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98156"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98156"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98156.mbox"},{"url":"https://git.kernel.org/stable/c/32e999ccf5f6453b3b4df8264ff1b03c6720292f"},{"url":"https://git.kernel.org/stable/c/3f130cc6826fabf50e01fe8e4ff3ed1fcae50d36"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.0014,"epssPercentile":0.03291,"scores":{"nvd":7.8,"vendor":7,"cna":7.8},"ingestedAt":"2026-09-25T11:06:38.803Z","slug":"CVE-2026-98156","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\ndrm/virtio: use the DMA API for resource backing on Xen\n\nOn a Xen PV domain page addresses bear no relation to the real machine\naddresses the host would have to use to reach it.\nvirtio_ring.c handles this correctly, vring_use_map_api() returns true\nfor any xen_domain() regardless of VIRTIO_F_ACCESS_PLATFORM.\n\nvirtio-gpu makes the same decision independently, but its copy\nlooks only at the feature bit:\n\n\tbool use_dma_api = !virtio_has_dma_quirk(vgdev->vdev);\n\nQEMU does not set iommu_platform on virtio-vga by default, so\nVIRTIO_F_ACCESS_PLATFORM is not negotiated, use_dma_api is false, and\nvirtio_gpu_object_shmem_init() describes the framebuffer's backing pages\nto the host with sg_phys().  Those are guest-physical addresses. In a PV\ndomain they resolve, on the host side, to pages belonging to some other\ndomain, so the host scans out unrelated memory.\n\nMove the decision into virtio_gpu_use_dma_api() and give it the\nxen_domain() check, like vring_use_map_api() has. This\nadditionally enables the dma_sync_sgtable_for_device() calls in\nvirtgpu_vq.c, which are required for correctness whenever swiotlb\nis in play.\n\nReproduced with a Xen 4.21 PV dom0 nested inside QEMU 8.2 with\nvirtio-vga, on both a distro 6.8 kernel and 6.18 LTS. A PVH dom0\nworks fine and doesn't need this fix because it is identity-mapped,\nonly PV dom0s are affected.\n\n## Affected\n\n- `linux_kernel >= 4.20, < 6.18.53`\n- `linux_kernel >= 6.19, < 7.2.7`\n- `linux_kernel = 7.3`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 7.2.7`\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-28 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98156.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":210886,"id":"CVE-2026-98156","ts":1790349112869,"field":"cvss","old":null,"new":"7.8"},{"seq":210885,"id":"CVE-2026-98156","ts":1790349112869,"field":"severity","old":"none","new":"high"}]}