{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-63845",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-63845"
  ],
  "published": "2026-07-19T14:05:10Z",
  "summary": "drm/amdgpu/jpeg: set no_user_fence for JPEG v4.0 ring",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amdgpu/jpeg: set no_user_fence for JPEG v4.0 ring\n\nJPEG rings do not support 64-bit user fence writes, reject CS\nsubmissions with user fences.\n\n(cherry picked from commit 8d0cac9478a3f046279c657d6a2545de49ae675a)",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": null,
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-63845"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d4e0172a1b614373385e9b7111b580f8d2e0b98f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a676f16ea9a7df96d69f405afb6eb349571b3382"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/6876d05b899102f4dfdb9ad560132126144c1c72"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/af4b458daa597dae707bf3f1f74745f5fc133ca2"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/e7e90b5839aeb8805ec83bb4da610b8dab8e184d"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T13:16:28Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - Exploitation requires a local DRM render-node client to issue DRM_IOCTL_AMDGPU_CS; the vulnerable path runs when amdgpu_cs_ioctl accepts a command submission with an AMDGPU_CHUNK_ID_FENCE user fence targeting the JPEG v4.0 decode ring (AMDGPU_HW_IP_VCN_JPEG).\nAC:L - An attacker with render-node access can deterministically submit a JPEG-ring CS with a user-fence chunk; no race or victim-dependent timing is required beyond having an affected VCN 4.0.0/4.0.2/4.0.4 AMD GPU (RDNA3-class hardware).\nPR:L - Only a local unprivileged user able to open /dev/dri/renderD* and submit CS jobs is needed; amdgpu_cs_ioctl is exposed to render clients (DRM_RENDER_ALLOW) without requiring root or DRM master privileges.\nUI:N - No victim interaction is required; the attacker directly crafts and submits the malicious ioctl from their own GPU client process.\nS:U - The corrupted GPU fence write is performed through the submitting context's GPU VM and does not cross a VM/host or IOMMU security boundary; impact remains within the attacker's kernel/GPU security scope (local privilege escalation scenario).\nC:H - amdgpu_ib.c always emits user fences with AMDGPU_FENCE_FLAG_64BIT, but jpeg_v2_0_dec_ring_emit_fence (used by JPEG v4.0) only supports 32-bit writes and WARN_ONs the 64-bit flag, causing the hardware to perform an unsupported GPU memory write that can corrupt memory and be leveraged for information disclosure.\nI:H - The unsupported fence path issues a GPU MEM_WR to an attacker-chosen GPU virtual address, providing a memory-corruption primitive that can be developed into arbitrary writes and potential kernel code execution.\nA:H - Submitting an unsupported 64-bit user fence to the JPEG ring can hang or reset the GPU and destabilize the amdgpu driver, causing denial of service to GPU workloads and potential system-wide availability impact."
    }
  }
}