{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-64524",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-64524"
  ],
  "published": "2026-07-25T09:19:40Z",
  "summary": "drm/hyperv: validate resolution_count and fix WIN8 fallback",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/hyperv: validate resolution_count and fix WIN8 fallback\n\nA SYNTHVID_RESOLUTION_RESPONSE with resolution_count > 64 walks past\nthe supported_resolution[SYNTHVID_MAX_RESOLUTION_COUNT] array in the\nparse loop. Bound resolution_count against the array size, folded\ninto the existing zero-check.\n\nWhen the WIN10 resolution probe fails, the caller in\nhyperv_connect_vsp() left hv->screen_*_max / preferred_* unpopulated,\nwhich sets mode_config.max_width / max_height to 0 and makes\ndrm_internal_framebuffer_create() reject every userspace framebuffer\nwith -EINVAL. The pre-WIN10 branch had the same gap for\npreferred_width / preferred_height. Use a single post-probe fallback\nguarded by screen_width_max == 0 so both paths converge on the WIN8\ndefaults.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/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": "6.1.176",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-64524"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/96f7de3172d4aa878b7f87173b2b3507c350fcd6"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/bc573752f3dac0d1ab8df7078c1851bc76717653"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1fb565b77b8f44afabb02de6310065f109d89e94"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a321c908f2eeea01539668eb270d074d9b88e490"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9c698b2c43c2667c34f5336bf46ad5786216ac2a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8a114b25b5521eae451b13bce98ae978624962e5"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/13d33b9ef67066c77c84273fac5a1d3fde3533d1"
    }
  ],
  "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": 7.7,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The malicious resolution response must originate from the local Hyper-V synthetic-video backend over VMBus; it is not reachable through a network protocol or guest userspace ioctl.\nAC:L - The backend can deterministically trigger the flaw by returning a resolution_count from 65 through 255 during the normal WIN10+ probe or resume exchange, without a race or unpredictable condition.\nPR:N - The guest accepts the VMBus response without authentication, capability checks, or guest credentials; a malicious or compromised backend requires no privileges within the vulnerable guest.\nUI:N - The response is processed automatically during device probing or resume, without any victim action.\nS:U - The vulnerable parser and the affected DRM and kernel resources are within the same guest-kernel security authority; this does not produce a guest-to-host escape.\nC:H - A count of 255 causes 191 additional four-byte entries to be read beyond the declared array, substantially exceeding a small bounded disclosure and allowing out-of-bounds kernel data to influence observable display state.\nI:N - The invalid accesses are reads, and their results are written only to the intended resolution fields; no out-of-bounds write, use-after-free, or control-flow corruption was found.\nA:H - Bounds-instrumented hardened kernels can oops when index 64 is reached, while a failed or malformed resolution probe can leave zero maximum dimensions and make every userspace framebuffer creation fail."
    }
  }
}