CVE-2026-63852 (GCVE-0-2026-63852)
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 v4.0.3 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 ff1a5a125c5a70c328806b9bc01d7d942cf3f9aa)
References
Impacted products
Vendor Product Version
Linux Linux Version: b889ef4ac98837838c38f7b9f72bba2f33ee367d
Version: b889ef4ac98837838c38f7b9f72bba2f33ee367d
Version: b889ef4ac98837838c38f7b9f72bba2f33ee367d
Version: b889ef4ac98837838c38f7b9f72bba2f33ee367d
Version: b889ef4ac98837838c38f7b9f72bba2f33ee367d
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/amd/amdgpu/vcn_v4_0_3.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "c12a5d35033c0640c57c10d7111c010c7b9c2c8e",
              "status": "affected",
              "version": "b889ef4ac98837838c38f7b9f72bba2f33ee367d",
              "versionType": "git"
            },
            {
              "lessThan": "387b7c7667bd5c53549350ddad866d2fcf75a529",
              "status": "affected",
              "version": "b889ef4ac98837838c38f7b9f72bba2f33ee367d",
              "versionType": "git"
            },
            {
              "lessThan": "9076a83e5adefd10dc5c967c7b8bde601c4c512a",
              "status": "affected",
              "version": "b889ef4ac98837838c38f7b9f72bba2f33ee367d",
              "versionType": "git"
            },
            {
              "lessThan": "0177ac6141c8857130cf365369c74dee7b6b1f7f",
              "status": "affected",
              "version": "b889ef4ac98837838c38f7b9f72bba2f33ee367d",
              "versionType": "git"
            },
            {
              "lessThan": "4532b52b34e4e4310386e6fdf6a643368599f522",
              "status": "affected",
              "version": "b889ef4ac98837838c38f7b9f72bba2f33ee367d",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/amd/amdgpu/vcn_v4_0_3.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.5"
            },
            {
              "lessThan": "6.5",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.141",
              "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": "6.6.141",
                  "versionStartIncluding": "6.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.91",
                  "versionStartIncluding": "6.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.33",
                  "versionStartIncluding": "6.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.10",
                  "versionStartIncluding": "6.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.5",
                  "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 v4.0.3 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 ff1a5a125c5a70c328806b9bc01d7d942cf3f9aa)"
        }
      ],
      "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 - The vulnerable code is reached only through DRM_IOCTL_AMDGPU_CS on an AMDGPU render node (/dev/dri/renderD*), requiring a local ioctl from userspace to submit command streams with a user fence chunk to the VCN v4.0.3 unified encoder ring.\nAC:L - On affected VCN 4.0.3 hardware, an attacker fully controls CS submission parameters (fence GEM handle, offset, and VCN_ENC ring IB) and can reliably trigger the unsupported 64-bit user fence path without races or external timing dependencies.\nPR:L - DRM_IOCTL_AMDGPU_CS is gated by DRM_AUTH|DRM_RENDER_ALLOW, so any unprivileged local user with render-node access (typically membership in the render group) can reach the vulnerable path without root or special capabilities.\nUI:N - Exploitation requires only programmatic ioctl submission; no victim interaction such as opening files, mounting filesystems, or clicking prompts is needed.\nS:U - The flaw enables GPU-initiated memory corruption within the attacker\u0027s own AMDGPU context/VM via the render node, which is a standard local kernel/GPU-driver privilege boundary rather than a cross-authority escape such as VM guest-to-host or IOMMU bypass.\nC:H - Submitting a 64-bit user fence to a ring that only supports 32-bit fence writes causes the VCN hardware to perform misdirected or out-of-bounds GPU memory writes, providing a memory-corruption primitive that can be leveraged for information disclosure.\nI:H - The unsupported fence write gives the attacker a GPU-initiated arbitrary-write primitive at attacker-chosen GPU virtual addresses within their VM mappings, which is memory corruption exploitable for further integrity compromise or code execution.\nA:H - Incorrect fence handling on the VCN encoder ring can hang or fault the GPU, trigger driver error-recovery paths, and cause system-wide graphics disruption or kernel oops, constituting high availability impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:36:30.612Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/c12a5d35033c0640c57c10d7111c010c7b9c2c8e"
        },
        {
          "url": "https://git.kernel.org/stable/c/387b7c7667bd5c53549350ddad866d2fcf75a529"
        },
        {
          "url": "https://git.kernel.org/stable/c/9076a83e5adefd10dc5c967c7b8bde601c4c512a"
        },
        {
          "url": "https://git.kernel.org/stable/c/0177ac6141c8857130cf365369c74dee7b6b1f7f"
        },
        {
          "url": "https://git.kernel.org/stable/c/4532b52b34e4e4310386e6fdf6a643368599f522"
        }
      ],
      "title": "drm/amdgpu/vcn: set no_user_fence for VCN v4.0.3 enc ring",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63852",
    "datePublished": "2026-07-19T14:04:43.258Z",
    "dateReserved": "2026-07-19T07:54:57.016Z",
    "dateUpdated": "2026-08-05T12:36:30.612Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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