CVE-2026-63849 (GCVE-0-2026-63849)

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 v5.0.1 enc ring
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu/vcn: set no_user_fence for VCN v5.0.1 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 e16be95a2c3ee712b142cb27d2dca0b461181359)
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: 346492f30ce3581bf5324c4ae417eab8537dc998 , < 081ef0e46c9cdd26c0db0ef721470393d36b6655 (git)
Affected: 346492f30ce3581bf5324c4ae417eab8537dc998 , < 5a4bffd67e94944ed3db26a959346cfb7fabaecd (git)
Affected: 346492f30ce3581bf5324c4ae417eab8537dc998 , < 8f4954722eab88e10c4ea0c0d3b1269c31421d3a (git)
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Linux Linux Affected: 6.14
Unaffected: 0 , < 6.14 (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_1.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "081ef0e46c9cdd26c0db0ef721470393d36b6655",
              "status": "affected",
              "version": "346492f30ce3581bf5324c4ae417eab8537dc998",
              "versionType": "git"
            },
            {
              "lessThan": "5a4bffd67e94944ed3db26a959346cfb7fabaecd",
              "status": "affected",
              "version": "346492f30ce3581bf5324c4ae417eab8537dc998",
              "versionType": "git"
            },
            {
              "lessThan": "8f4954722eab88e10c4ea0c0d3b1269c31421d3a",
              "status": "affected",
              "version": "346492f30ce3581bf5324c4ae417eab8537dc998",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/amd/amdgpu/vcn_v5_0_1.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "lessThan": "6.14",
              "status": "unaffected",
              "version": "0",
              "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": "6.18.33",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.10",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.14",
                  "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 v5.0.1 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 e16be95a2c3ee712b142cb27d2dca0b461181359)"
        }
      ],
      "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 vulnerability is reached only through local DRM ioctls (primarily DRM_IOCTL_AMDGPU_CS on a /dev/dri/renderD* node), not over any network protocol.\nAC:L - An attacker with render-node access can deterministically submit a VCN_ENC command buffer with an AMDGPU_CHUNK_ID_FENCE chunk; no race or attacker-uncontrollable conditions are required beyond having the affected AMDGPU hardware.\nPR:L - Exploitation requires only local access to the GPU render node as an unprivileged user (DRM_AUTH|DRM_RENDER_ALLOW); no root or special capabilities are needed.\nUI:N - Triggering the bug requires only the attacker\u0027s own ioctl submissions; no action by another user or victim is required.\nS:U - Impact is confined to the attacker\u0027s GPU command-submission context and process GPU virtual address space; it does not cross a VM/host or other security-boundary scope.\nC:H - The unsupported 64-bit user-fence path causes the VCN engine to perform GPU memory writes to attacker-influenced addresses, which constitutes exploitable memory corruption that can be leveraged for information disclosure.\nI:H - The malformed fence write gives the attacker a GPU-initiated arbitrary memory write primitive within their GPU VA space, which can corrupt adjacent buffers and be chained toward code execution.\nA:H - Submitting unsupported user fences to the VCN ring can hang or reset the GPU and trigger kernel driver errors, causing denial of service on affected systems."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:36:27.366Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/081ef0e46c9cdd26c0db0ef721470393d36b6655"
        },
        {
          "url": "https://git.kernel.org/stable/c/5a4bffd67e94944ed3db26a959346cfb7fabaecd"
        },
        {
          "url": "https://git.kernel.org/stable/c/8f4954722eab88e10c4ea0c0d3b1269c31421d3a"
        }
      ],
      "title": "drm/amdgpu/vcn: set no_user_fence for VCN v5.0.1 enc ring",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63849",
    "datePublished": "2026-07-19T14:04:41.395Z",
    "dateReserved": "2026-07-19T07:54:57.016Z",
    "dateUpdated": "2026-08-05T12:36:27.366Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-63849",
      "date": "2026-10-07",
      "epss": "0.00173",
      "percentile": "0.06145"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "drivers/gpu/drm/amd/amdgpu/vcn_v5_0_1.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "081ef0e46c9cdd26c0db0ef721470393d36b6655",
                    "status": "affected",
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                    "versionType": "git"
                  },
                  {
                    "lessThan": "5a4bffd67e94944ed3db26a959346cfb7fabaecd",
                    "status": "affected",
                    "version": "346492f30ce3581bf5324c4ae417eab8537dc998",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "8f4954722eab88e10c4ea0c0d3b1269c31421d3a",
                    "status": "affected",
                    "version": "346492f30ce3581bf5324c4ae417eab8537dc998",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "drivers/gpu/drm/amd/amdgpu/vcn_v5_0_1.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
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                  },
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                    "version": "0",
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                  },
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                    "status": "unaffected",
                    "version": "6.18.33",
                    "versionType": "semver"
                  },
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                    "status": "unaffected",
                    "version": "7.0.10",
                    "versionType": "semver"
                  },
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                    "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 v5.0.1 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 e16be95a2c3ee712b142cb27d2dca0b461181359)"
          }
        ],
        "id": "CVE-2026-63849",
        "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": "2026-07-19T15:16:51.703",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/081ef0e46c9cdd26c0db0ef721470393d36b6655"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/5a4bffd67e94944ed3db26a959346cfb7fabaecd"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/8f4954722eab88e10c4ea0c0d3b1269c31421d3a"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Awaiting Analysis"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-07-31T19:34:48+00:00",
      "cve": "CVE-2026-63849",
      "id": "CVE-2026-63849",
      "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 v5.0.1 enc ring",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63849.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-10-01T00:50:05Z",
      "cve": "CVE-2026-63849",
      "id": "CVE-2026-63849",
      "initial_release_date": "2026-07-24T02:13:44Z",
      "product_status:known_not_affected": "362",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-63849",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-63849.json",
      "version": "4"
    }
  }
}



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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

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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.



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.