i3c: dw: avoid shift-out-of-bounds when DAA assigns no devices

{
  "id": "5db2d4a121c8a572577c92e6f3a012ee0e948c0cb228f551f2b85d266964aff2",
  "url": "https://osv.dev/vulnerability/CVE-2026-90386",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "i3c: dw: avoid shift-out-of-bounds when DAA assigns no devices",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: i3c: dw: avoid shift-out-of-bounds when DAA assigns no devices On an empty bus ENTDAA assigns nothing, so cmd->rx_len (the count of addresses left unassigned) equals master->maxdevs. The GENMASK() index master->maxdevs - cmd->rx_len - 1 then becomes -1, which trips up UBSAN. This happens every time on boot on a Gigabyte/AMD server: UBSAN: shift-out-of-bounds in drivers/i3c/master/dw-i3c-master.c:905:12 shift exponent 64 is too large for 64-bit type 'long unsigned int' CPU: 7 UID: 0 PID: 963 Comm: (udev-worker) Not tainted 7.0.11-200.fc44.x86_64 #1 PREEMPT(lazy) Hardware name: Giga Computing E163-Z34-AAH1-000/MZ33-DC1-000, BIOS R32_F45 04/01/2026 Call Trace: dump_stack_lvl+0x5d/0x80 ubsan_epilogue+0x5/0x2b __ubsan_handle_shift_out_of_bounds.cold+0xd7/0x1ab dw_i3c_master_daa.cold+0x1b/0x96 [dw_i3c_master] i3c_master_do_daa_ext.part.0+0x3e/0xf0 [i3c] Skip the mask when no new device was assigned.",
    "evidence": "osv:CVE-2026-90386",
    "products": [
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        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
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        "affected_versions": []
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    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-90386",
      "aliases": [
        "CVE-2026-90386"
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      "affected": [
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            "ecosystem": "Linux"
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      ],
      "modified": "2026-10-28T02:30:21.683551056Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/038cf48b3170af26a70bf2dee4f8c3ac910f5176",
        "https://git.kernel.org/stable/c/111f559e5b6461f5f6977275716e6c5d1eb7ea27",
        "https://git.kernel.org/stable/c/3a1c35739efb69e8ec2a868113a0471a01bb8f29",
        "https://git.kernel.org/stable/c/5650b013e6bfc14c8b30be727f4a715b01860a08",
        "https://git.kernel.org/stable/c/618dd640ded6b94bbdb79c798a901ec564797033",
        "https://git.kernel.org/stable/c/63110ccc434e10d9e9d2c7d82ebfa8a6f9cedd94",
        "https://git.kernel.org/stable/c/754533e6169d1f10bdef7a6ba9bd7740b524e1d4",
        "https://git.kernel.org/stable/c/9eaac0cb4ca94e2e32c53c156ae5b813ba7ef90c",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90386.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-90386",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90386.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-90386",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 487877,
  "published_at": "2026-09-17T16:09:21.842+00:00"
}