CVE-2026-63851 (GCVE-0-2026-63851)

Vulnerability from cvelistv5 – Published: 2026-07-19 14:04 – Updated: 2026-08-05 12:36
VLAI
Title
drm/amdgpu/vcn: set no_user_fence for VCN v4.0.5 enc ring
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)
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 547aad32edac17a3ec4989d8aad2426d0cbeb590 , < 75091030f07b7957cc0646cd52e2d9d15f611483 (git)
Affected: 547aad32edac17a3ec4989d8aad2426d0cbeb590 , < 6d9a98c5ed65ba92a09e4ca5a5f6941448145529 (git)
Affected: 547aad32edac17a3ec4989d8aad2426d0cbeb590 , < 7f23b5c420b9f68a210c29c5123bace670aa8cc9 (git)
Affected: 547aad32edac17a3ec4989d8aad2426d0cbeb590 , < 589a254bf3e88204c8402b9cbccd5e23a0af990f (git)
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Linux Linux Affected: 6.7
Unaffected: 0 , < 6.7 (semver)
Unaffected: 6.12.91 , ≤ 6.12.* (semver)
Unaffected: 6.18.33 , ≤ 6.18.* (semver)
Unaffected: 7.0.10 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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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",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-63851",
      "date": "2026-09-21",
      "epss": "0.00132",
      "percentile": "0.03141"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "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"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "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)"
          }
        ],
        "id": "CVE-2026-63851",
        "lastModified": "2026-07-27T17:44:23.777",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-07-19T15:16:51.907",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/589a254bf3e88204c8402b9cbccd5e23a0af990f"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/6d9a98c5ed65ba92a09e4ca5a5f6941448145529"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/75091030f07b7957cc0646cd52e2d9d15f611483"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/7f23b5c420b9f68a210c29c5123bace670aa8cc9"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Awaiting Analysis"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-08-05T14:05:47+00:00",
      "cve": "CVE-2026-63851",
      "id": "CVE-2026-63851",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_affected": "198",
      "product_status:known_not_affected": "76",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: drm/amdgpu/vcn: set no_user_fence for VCN v4.0.5 enc ring",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63851.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-18T00:47:31Z",
      "cve": "CVE-2026-63851",
      "id": "CVE-2026-63851",
      "initial_release_date": "2026-07-24T02:13:40Z",
      "product_status:first_fixed": "2",
      "product_status:known_affected": "482",
      "product_status:known_not_affected": "229",
      "product_status:recommended": "250",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-63851",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-63851.json",
      "version": "9"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.