CVE-2026-63851 (GCVE-0-2026-63851)
Vulnerability from cvelistv5
Published
2026-07-19 14:04
Modified
2026-08-05 12:36
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/amdgpu/vcn: set no_user_fence for VCN v4.0.5 enc ring VCN encoder and decoder rings do not support 64-bit user fence writes, reject CS submissions with user fences. (cherry picked from commit 084d94ac93707bdda07efb5cee786f632de4219b)
References
Impacted products
Vendor Product Version
Linux Linux Version: 547aad32edac17a3ec4989d8aad2426d0cbeb590
Version: 547aad32edac17a3ec4989d8aad2426d0cbeb590
Version: 547aad32edac17a3ec4989d8aad2426d0cbeb590
Version: 547aad32edac17a3ec4989d8aad2426d0cbeb590
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/amd/amdgpu/vcn_v4_0_5.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "75091030f07b7957cc0646cd52e2d9d15f611483",
              "status": "affected",
              "version": "547aad32edac17a3ec4989d8aad2426d0cbeb590",
              "versionType": "git"
            },
            {
              "lessThan": "6d9a98c5ed65ba92a09e4ca5a5f6941448145529",
              "status": "affected",
              "version": "547aad32edac17a3ec4989d8aad2426d0cbeb590",
              "versionType": "git"
            },
            {
              "lessThan": "7f23b5c420b9f68a210c29c5123bace670aa8cc9",
              "status": "affected",
              "version": "547aad32edac17a3ec4989d8aad2426d0cbeb590",
              "versionType": "git"
            },
            {
              "lessThan": "589a254bf3e88204c8402b9cbccd5e23a0af990f",
              "status": "affected",
              "version": "547aad32edac17a3ec4989d8aad2426d0cbeb590",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/amd/amdgpu/vcn_v4_0_5.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.7"
            },
            {
              "lessThan": "6.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.91",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.33",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.91",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.33",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.10",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amdgpu/vcn: set no_user_fence for VCN v4.0.5 enc ring\n\nVCN encoder and decoder rings do not support 64-bit user fence writes,\nreject CS submissions with user fences.\n\n(cherry picked from commit 084d94ac93707bdda07efb5cee786f632de4219b)"
        }
      ],
      "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 - Exploitation requires submitting AMDGPU command streams via the DRM render node (DRM_IOCTL_AMDGPU_CS), which is a local ioctl/device-file interface with no network-facing entry point.\nAC:L - An attacker with render-node access can deterministically craft a CS submission with a FENCE chunk targeting the VCN_ENC ring; no race conditions or attacker-uncontrollable timing are required.\nPR:L - The only gate is access to /dev/dri/renderD* (DRM_AUTH|DRM_RENDER_ALLOW), which is available to unprivileged local users in the render/video group and does not require root or capabilities obtainable only in the init namespace.\nUI:N - Once the attacker has render-node access, triggering the bug requires no additional victim interaction beyond normal GPU command submission.\nS:U - Impact is confined to the same local security domain (kernel/GPU driver); exploitation does not cross a VM, container, or IOMMU security boundary to a different authority.\nC:H - The unsupported GPU fence operation causes the VCN hardware to perform DMA writes outside the driver\u0027s validated semantics, creating a memory-corruption primitive that could expose or corrupt GPU-mapped memory beyond the intended 8-byte fence slot.\nI:H - The bug enables GPU-initiated writes to attacker-chosen GPU virtual addresses (user fence buffer), and hardware misbehavior on unsupported fence commands can corrupt adjacent or shared dma-buf memory with unpredictable write patterns.\nA:H - Submitting unsupported user fences to the VCN ring can hang the GPU, trigger VCN poison/RAS interrupts, or crash the graphics subsystem, causing denial of service on affected systems."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:36:29.527Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/75091030f07b7957cc0646cd52e2d9d15f611483"
        },
        {
          "url": "https://git.kernel.org/stable/c/6d9a98c5ed65ba92a09e4ca5a5f6941448145529"
        },
        {
          "url": "https://git.kernel.org/stable/c/7f23b5c420b9f68a210c29c5123bace670aa8cc9"
        },
        {
          "url": "https://git.kernel.org/stable/c/589a254bf3e88204c8402b9cbccd5e23a0af990f"
        }
      ],
      "title": "drm/amdgpu/vcn: set no_user_fence for VCN v4.0.5 enc ring",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63851",
    "datePublished": "2026-07-19T14:04:42.581Z",
    "dateReserved": "2026-07-19T07:54:57.016Z",
    "dateUpdated": "2026-08-05T12:36:29.527Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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