CVE-2026-63852 (GCVE-0-2026-63852)

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 v4.0.3 enc ring
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)
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: b889ef4ac98837838c38f7b9f72bba2f33ee367d , < c12a5d35033c0640c57c10d7111c010c7b9c2c8e (git)
Affected: b889ef4ac98837838c38f7b9f72bba2f33ee367d , < 387b7c7667bd5c53549350ddad866d2fcf75a529 (git)
Affected: b889ef4ac98837838c38f7b9f72bba2f33ee367d , < 9076a83e5adefd10dc5c967c7b8bde601c4c512a (git)
Affected: b889ef4ac98837838c38f7b9f72bba2f33ee367d , < 0177ac6141c8857130cf365369c74dee7b6b1f7f (git)
Affected: b889ef4ac98837838c38f7b9f72bba2f33ee367d , < 4532b52b34e4e4310386e6fdf6a643368599f522 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.5
Unaffected: 0 , < 6.5 (semver)
Unaffected: 6.6.141 , ≤ 6.6.* (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)
guessed Create a notification for this product.
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{
  "containers": {
    "cna": {
      "affected": [
        {
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          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/amd/amdgpu/vcn_v4_0_3.c"
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          "vendor": "Linux",
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              "version": "0",
              "versionType": "semver"
            },
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              "version": "6.6.141",
              "versionType": "semver"
            },
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              "version": "6.12.91",
              "versionType": "semver"
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              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "7.0.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "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:*:*:*:*:*:*:*:*",
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              "negate": false,
              "operator": "OR"
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      ],
      "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": [
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            "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."
            }
          ]
        }
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      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:36:30.612Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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        },
        {
          "url": "https://git.kernel.org/stable/c/4532b52b34e4e4310386e6fdf6a643368599f522"
        }
      ],
      "title": "drm/amdgpu/vcn: set no_user_fence for VCN v4.0.3 enc ring",
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    "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"
  },
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  "dataVersion": "5.2",
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      "date": "2026-09-21",
      "epss": "0.00132",
      "percentile": "0.0314"
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            "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)"
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        "lastModified": "2026-07-27T17:44:23.777",
        "metrics": {
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                "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",
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              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-31T19:23:12+00:00",
      "cve": "CVE-2026-63852",
      "id": "CVE-2026-63852",
      "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 v4.0.3 enc ring",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63852.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-18T00:47:29Z",
      "cve": "CVE-2026-63852",
      "id": "CVE-2026-63852",
      "initial_release_date": "2026-07-24T02:13:37Z",
      "product_status:first_fixed": "2",
      "product_status:known_affected": "424",
      "product_status:known_not_affected": "297",
      "product_status:recommended": "250",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-63852",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-63852.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.

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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.
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  • 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.



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