CVE-2026-63850 (GCVE-0-2026-63850)

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 v5.0.0 enc ring
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu/vcn: set no_user_fence for VCN v5.0.0 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 49b1fbbb5a071197ee71e2d70959b1cb29bdc317)
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: b6d1a06320519ac3bfda6ce81067a1bc409b9cff , < 9f5a1459ecc3195282be617639d710b54779c9dc (git)
Affected: b6d1a06320519ac3bfda6ce81067a1bc409b9cff , < 139a8a52ef4349c62129703b3a3e3a6ae4d634eb (git)
Affected: b6d1a06320519ac3bfda6ce81067a1bc409b9cff , < 2c350f3cd94be847ac216e1358ec7001eaaf0934 (git)
Affected: b6d1a06320519ac3bfda6ce81067a1bc409b9cff , < 8cae0ce77de492d7c31c1532a2e80c0c6e7e58cb (git)
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Linux Linux Affected: 6.9
Unaffected: 0 , < 6.9 (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_v5_0_0.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "9f5a1459ecc3195282be617639d710b54779c9dc",
              "status": "affected",
              "version": "b6d1a06320519ac3bfda6ce81067a1bc409b9cff",
              "versionType": "git"
            },
            {
              "lessThan": "139a8a52ef4349c62129703b3a3e3a6ae4d634eb",
              "status": "affected",
              "version": "b6d1a06320519ac3bfda6ce81067a1bc409b9cff",
              "versionType": "git"
            },
            {
              "lessThan": "2c350f3cd94be847ac216e1358ec7001eaaf0934",
              "status": "affected",
              "version": "b6d1a06320519ac3bfda6ce81067a1bc409b9cff",
              "versionType": "git"
            },
            {
              "lessThan": "8cae0ce77de492d7c31c1532a2e80c0c6e7e58cb",
              "status": "affected",
              "version": "b6d1a06320519ac3bfda6ce81067a1bc409b9cff",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/amd/amdgpu/vcn_v5_0_0.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.9"
            },
            {
              "lessThan": "6.9",
              "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": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.33",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.10",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.9",
                  "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 v5.0.0 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 49b1fbbb5a071197ee71e2d70959b1cb29bdc317)"
        }
      ],
      "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 via the local DRM_IOCTL_AMDGPU_CS ioctl on an AMDGPU render node (/dev/dri/renderD*), submitting a command buffer with AMDGPU_CHUNK_ID_FENCE to the VCN v5.0.0 encoder ring.\nAC:L - An attacker with render-node access can deterministically submit a VCN encoder CS with a user-fence chunk; no race, special memory layout, or non-default kernel configuration is required beyond having affected AMD VCN 5.0.0 hardware.\nPR:L - Exploitation requires access to the AMDGPU DRM render node, which is available to unprivileged local users in the render/video group (or equivalent GPU access), not root or capabilities obtainable only in the init namespace.\nUI:N - No victim interaction is needed beyond the attacker already having GPU render-node access; exploitation is fully attacker-driven through ioctl submission.\nS:U - Impact is kernel/GPU memory corruption and privilege escalation within the same host security boundary; it does not inherently cross a VM, container, or IOMMU isolation boundary.\nC:H - Submitting an unsupported 64-bit user fence causes the VCN hardware to perform misdirected GPU memory writes, providing a memory-corruption primitive that can be leveraged for arbitrary kernel memory disclosure.\nI:H - The malformed fence write gives the attacker a GPU-initiated arbitrary write primitive within the GPU virtual address space, enabling memory corruption and potential kernel code execution.\nA:H - Malformed VCN fence commands can hang the GPU, trigger kernel oopses, or crash the system when the unsupported fence operation is processed by hardware."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:36:28.456Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/9f5a1459ecc3195282be617639d710b54779c9dc"
        },
        {
          "url": "https://git.kernel.org/stable/c/139a8a52ef4349c62129703b3a3e3a6ae4d634eb"
        },
        {
          "url": "https://git.kernel.org/stable/c/2c350f3cd94be847ac216e1358ec7001eaaf0934"
        },
        {
          "url": "https://git.kernel.org/stable/c/8cae0ce77de492d7c31c1532a2e80c0c6e7e58cb"
        }
      ],
      "title": "drm/amdgpu/vcn: set no_user_fence for VCN v5.0.0 enc ring",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63850",
    "datePublished": "2026-07-19T14:04:41.975Z",
    "dateReserved": "2026-07-19T07:54:57.016Z",
    "dateUpdated": "2026-08-05T12:36:28.456Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-63850",
      "date": "2026-09-21",
      "epss": "0.00142",
      "percentile": "0.03828"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "drivers/gpu/drm/amd/amdgpu/vcn_v5_0_0.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "9f5a1459ecc3195282be617639d710b54779c9dc",
                    "status": "affected",
                    "version": "b6d1a06320519ac3bfda6ce81067a1bc409b9cff",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "139a8a52ef4349c62129703b3a3e3a6ae4d634eb",
                    "status": "affected",
                    "version": "b6d1a06320519ac3bfda6ce81067a1bc409b9cff",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "2c350f3cd94be847ac216e1358ec7001eaaf0934",
                    "status": "affected",
                    "version": "b6d1a06320519ac3bfda6ce81067a1bc409b9cff",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "8cae0ce77de492d7c31c1532a2e80c0c6e7e58cb",
                    "status": "affected",
                    "version": "b6d1a06320519ac3bfda6ce81067a1bc409b9cff",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "drivers/gpu/drm/amd/amdgpu/vcn_v5_0_0.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "6.9"
                  },
                  {
                    "lessThan": "6.9",
                    "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 v5.0.0 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 49b1fbbb5a071197ee71e2d70959b1cb29bdc317)"
          }
        ],
        "id": "CVE-2026-63850",
        "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": "2026-07-19T15:16:51.803",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/139a8a52ef4349c62129703b3a3e3a6ae4d634eb"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/2c350f3cd94be847ac216e1358ec7001eaaf0934"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/8cae0ce77de492d7c31c1532a2e80c0c6e7e58cb"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/9f5a1459ecc3195282be617639d710b54779c9dc"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Awaiting Analysis"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-31T19:28:12+00:00",
      "cve": "CVE-2026-63850",
      "id": "CVE-2026-63850",
      "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 v5.0.0 enc ring",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63850.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-21T16:49:52Z",
      "cve": "CVE-2026-63850",
      "id": "CVE-2026-63850",
      "initial_release_date": "2026-07-24T02:13:42Z",
      "product_status:first_fixed": "2",
      "product_status:known_affected": "394",
      "product_status:known_not_affected": "332",
      "product_status:recommended": "228",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-63850",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-63850.json",
      "version": "7"
    }
  }
}



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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.