CVE-2026-98510 (GCVE-0-2026-98510)
Vulnerability from cvelistv5
Published
2026-10-18 15:17
Modified
2026-10-24 14:09
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/xe/vm: nuke PTs only after unlinking contested VMAs In xe_vm_close_and_put(), external-BO VMAs are queued on the contested list for deferred destruction via xe_vma_destroy_unlocked(). However, xe_vm_pt_destroy() was previously invoked before processing contested VMAs, destroying vm->pt_root while those VMAs were still linked to their respective buffer objects (vm_bo->list.gpuva). If a concurrent thread evicts one of those shared buffer objects, xe_bo_trigger_rebind() holding only bo->resv walks the BO's VMAs and, in fault mode, calls xe_vm_invalidate_vma() -> xe_pt_zap_ptes(). Because vm->pt_root[tile->id] is already NULL, dereferencing pt->level causes a NULL ptr deref. Fix this by deferring xe_vm_free_scratch() and xe_vm_pt_destroy() until after all contested VMAs have been unlinked and destroyed. User is reporting hitting a NULL ptr deref in xe_pt_zap_ptes(), which could be explained by this race. (cherry picked from commit c2863648959489767f08892fd6e90577d2ea0b6a)
References
Impacted products
Vendor Product Version
Linux Linux Version: b06d47be7c83165d3b3e45e1d5f9520b79c7f5cc
Version: b06d47be7c83165d3b3e45e1d5f9520b79c7f5cc
Version: b06d47be7c83165d3b3e45e1d5f9520b79c7f5cc
Version: b06d47be7c83165d3b3e45e1d5f9520b79c7f5cc
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/xe/xe_vm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "lessThan": "70fddc065ac80845ffd33095b3635d59883cf7e6",
              "status": "affected",
              "version": "b06d47be7c83165d3b3e45e1d5f9520b79c7f5cc",
              "versionType": "git"
            },
            {
              "lessThan": "ba678c2b02e0d36b53deb5a6d5e5ea044d36def7",
              "status": "affected",
              "version": "b06d47be7c83165d3b3e45e1d5f9520b79c7f5cc",
              "versionType": "git"
            },
            {
              "lessThan": "bddaa5e4094c134452c29e20a26c4718827e4cb1",
              "status": "affected",
              "version": "b06d47be7c83165d3b3e45e1d5f9520b79c7f5cc",
              "versionType": "git"
            },
            {
              "lessThan": "24a22fb3c731474b68e986af6804db450fb88617",
              "status": "affected",
              "version": "b06d47be7c83165d3b3e45e1d5f9520b79c7f5cc",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/xe/xe_vm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.8"
            },
            {
              "lessThan": "6.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.112",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.55",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.112",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.55",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.9",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/xe/vm: nuke PTs only after unlinking contested VMAs\n\nIn xe_vm_close_and_put(), external-BO VMAs are queued on the contested\nlist for deferred destruction via xe_vma_destroy_unlocked(). However,\nxe_vm_pt_destroy() was previously invoked before processing contested\nVMAs, destroying vm-\u003ept_root while those VMAs were still linked to their\nrespective buffer objects (vm_bo-\u003elist.gpuva).\n\nIf a concurrent thread evicts one of those shared buffer objects,\nxe_bo_trigger_rebind() holding only bo-\u003eresv walks the BO\u0027s VMAs and, in\nfault mode, calls xe_vm_invalidate_vma() -\u003e xe_pt_zap_ptes(). Because\nvm-\u003ept_root[tile-\u003eid] is already NULL, dereferencing pt-\u003elevel causes a\nNULL ptr deref.\n\nFix this by deferring xe_vm_free_scratch() and xe_vm_pt_destroy() until\nafter all contested VMAs have been unlinked and destroyed.\n\nUser is reporting hitting a NULL ptr deref in xe_pt_zap_ptes(), which\ncould be explained by this race.\n\n(cherry picked from commit c2863648959489767f08892fd6e90577d2ea0b6a)"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - A local render-node client reaches the patched xe_vm_close_and_put() through DRM_IOCTL_XE_VM_DESTROY -\u003e xe_vm_destroy_ioctl() or file close -\u003e xe_file_close(); the competing path is another local DRM ioctl, not wire-supplied data.\nAC:L - The same client can bind an external BO to a fault-mode VM and race VM_DESTROY against PREFETCH from a second VM; PREFETCH reaches xe_bo_migrate() -\u003e xe_bo_move_notify() -\u003e xe_bo_trigger_rebind(), so the attacker controls both sides.\nPR:L - XE_VM_CREATE, XE_GEM_CREATE, XE_VM_BIND, and XE_VM_DESTROY are registered with DRM_RENDER_ALLOW and contain no capability or DRM-authentication check, making the path available to an unprivileged user with render-node access.\nUI:N - The attacking process creates the VM and external BO, establishes the immediate mapping, and issues both the destroy and migration operations itself; no victim action is required.\nS:U - The fault occurs in the host xe DRM driver while processing that driver\u0027s local render-node operations and does not cross a VM, IOMMU, or other security authority boundary.\nC:H - xe_vm_close_and_put() leaves the VMA linked while xe_pt_destroy() recursively kfree()s PT nodes with vm-\u003ept_root still published; a racing xe_pt_zap_ptes() can therefore walk heap-groomable freed PT metadata and dereference stale object pointers.\nI:H - In the UAF interleaving, xe_pt_zap_ptes_entry() uses the freed metadata\u0027s xe_child-\u003ebo-\u003evmap as the destination for xe_map_memset(), allowing a groomed stale pointer to redirect writes and potentially corrupt control flow.\nA:H - In the documented interleaving, xe_vm_pt_destroy() sets vm-\u003ept_root[tile-\u003eid] to NULL and xe_pt_zap_ptes() dereferences pt-\u003elevel, producing the reported kernel NULL-pointer oops."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-24T14:09:11.598Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/70fddc065ac80845ffd33095b3635d59883cf7e6"
        },
        {
          "url": "https://git.kernel.org/stable/c/ba678c2b02e0d36b53deb5a6d5e5ea044d36def7"
        },
        {
          "url": "https://git.kernel.org/stable/c/bddaa5e4094c134452c29e20a26c4718827e4cb1"
        },
        {
          "url": "https://git.kernel.org/stable/c/24a22fb3c731474b68e986af6804db450fb88617"
        }
      ],
      "title": "drm/xe/vm: nuke PTs only after unlinking contested VMAs",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98510",
    "datePublished": "2026-10-18T15:17:20.805Z",
    "dateReserved": "2026-09-25T10:25:14.354Z",
    "dateUpdated": "2026-10-24T14:09:11.598Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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