drm/hyperv: validate resolution_count and fix WIN8 fallback

{
  "id": "a14c8525580ed783e52f366413e26d61f2a39b0a7519c3e4a14b92552d273587",
  "url": "https://osv.dev/vulnerability/CVE-2026-64524",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "drm/hyperv: validate resolution_count and fix WIN8 fallback",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: drm/hyperv: validate resolution_count and fix WIN8 fallback A SYNTHVID_RESOLUTION_RESPONSE with resolution_count > 64 walks past the supported_resolution[SYNTHVID_MAX_RESOLUTION_COUNT] array in the parse loop. Bound resolution_count against the array size, folded into the existing zero-check. When the WIN10 resolution probe fails, the caller in hyperv_connect_vsp() left hv->screen_*_max / preferred_* unpopulated, which sets mode_config.max_width / max_height to 0 and makes drm_internal_framebuffer_create() reject every userspace framebuffer with -EINVAL. The pre-WIN10 branch had the same gap for preferred_width / preferred_height. Use a single post-probe fallback guarded by screen_width_max == 0 so both paths converge on the WIN8 defaults.",
    "evidence": "osv:CVE-2026-64524",
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    "severity": "high",
    "structured": {
      "id": "CVE-2026-64524",
      "aliases": [
        "CVE-2026-64524"
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      "metrics": [
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          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H"
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      "modified": "2026-10-28T02:30:40.327204320Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/13d33b9ef67066c77c84273fac5a1d3fde3533d1",
        "https://git.kernel.org/stable/c/1fb565b77b8f44afabb02de6310065f109d89e94",
        "https://git.kernel.org/stable/c/8a114b25b5521eae451b13bce98ae978624962e5",
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        "https://git.kernel.org/stable/c/9c698b2c43c2667c34f5336bf46ad5786216ac2a",
        "https://git.kernel.org/stable/c/a321c908f2eeea01539668eb270d074d9b88e490",
        "https://git.kernel.org/stable/c/bc573752f3dac0d1ab8df7078c1851bc76717653",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64524.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-64524",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
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    "severity_evidence": "/severity/0/score"
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  "source_id": "core-osv",
  "document_id": 508128,
  "published_at": "2026-07-25T09:20:48.193+00:00"
}