{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2024-26914",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2024-26914"
  ],
  "published": "2024-04-17T15:59:47Z",
  "summary": "drm/amd/display: fix incorrect mpc_combine array size",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amd/display: fix incorrect mpc_combine array size\n\n[why]\nMAX_SURFACES is per stream, while MAX_PLANES is per asic. The\nmpc_combine is an array that records all the planes per asic. Therefore\nMAX_PLANES should be used as the array size. Using MAX_SURFACES causes\narray overflow when there are more than 3 planes.\n\n[how]\nUse the MAX_PLANES for the mpc_combine array size.",
  "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-2024-26914"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/0bd8ef618a42d7e6ea3f701065264e15678025e3"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/39079fe8e660851abbafa90cd55cbf029210661f"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T11:52:36Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The overflow is reached only through the local DRM atomic modeset ioctl (`DRM_IOCTL_MODE_ATOMIC`) on /dev/dri/cardN, which drives `amdgpu_dm_atomic_check()` \u2192 `dc_validate_global_state()` \u2192 `dcn32_internal_validate_bw()`. No network or remote data path reaches `dcn32_fpu.c`.\nAC:L - On an affected DCN3.2/3.2.1 ASIC the attacker fully controls the trigger \u2014 assigning four planes (two primaries plus two MPO overlays) across two CRTCs in a single atomic commit, even a TEST_ONLY one, deterministically pushes `mpc_combine_count` past the 3-entry array. No race, no timing window, no unpredictable memory layout is required.\nPR:L - The atomic ioctl requires DRM master, which an ordinary unprivileged user holds for their own graphical session (or obtains by opening the card first on a kiosk/embedded/automotive system with no running compositor); no root or capability in the init namespace is needed.\nUI:N - The attacker performs the entire sequence \u2014 configuring planes and issuing the atomic commit/test \u2014 from their own process; no other user must open a file, plug in hardware, or take any action.\nS:U - The corruption occurs in the kernel stack frame of the amdgpu display driver and stays within the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Clobbering `mpc_combine_count` with the low bits of a kernel pointer makes `update_pipes_with_slice_table()` and `update_slice_table_for_plane()` read hundreds of megabytes worth of out-of-bounds indices off the kernel stack and treat that data as `dc_plane_state`/`pipe_ctx` pointers, giving an out-of-bounds read primitive over kernel memory; per kernel CVSS guidance, memory corruption of this class is scored High.\nI:H - This is an out-of-bounds stack write: kernel pointer values are written past the end of `struct pipe_slice_table`, and the corrupted count subsequently allows an append at an attacker-uninfluenced-but-huge index, producing a wild write plus `slice_count += diff` increments at out-of-bounds addresses \u2014 an exploitable memory-corruption primitive.\nA:H - Once the count is corrupted into a multi-million value, the driver dereferences garbage pointers inside a `DC_FP_START()`/kernel_fpu section while holding the DC lock, which reliably produces an oops/panic and takes down the display pipeline."
    }
  }
}