usb: atm: usbatm: fix invalid ci_range initialization

{
  "id": "f96c2bfcb2971c27dd03f28b0fe490d70c200bd2fe5dd2b3a544879f67eeea35",
  "url": "https://osv.dev/vulnerability/CVE-2026-90055",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "usb: atm: usbatm: fix invalid ci_range initialization",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: usb: atm: usbatm: fix invalid ci_range initialization syzbot reported a shift-out-of-bounds in __vcc_connect(): UBSAN: shift-out-of-bounds in net/atm/common.c:382:32 shift exponent -1 is negative CPU: 0 UID: 0 PID: 5987 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233 __ubsan_handle_shift_out_of_bounds+0x36d/0x400 lib/ubsan.c:494 __vcc_connect+0x14b4/0x19c0 net/atm/common.c:382 vcc_connect+0x328/0x8f0 net/atm/common.c:498 pvc_bind+0x272/0x380 net/atm/pvc.c:52 __sys_bind+0x2e3/0x410 net/socket.c:1976 __x64_sys_bind+0x7a/0x90 net/socket.c:1979 ... ATM device ci_range fields (vpi_bits and vci_bits) represent the number of bits supported for VPI and VCI addressing on the device. net/atm/common.c directly uses these fields as bit shift counts: vpi >> dev->ci_range.vpi_bits vci >> dev->ci_range.vci_bits 1 << vcc->dev->ci_range.vpi_bits 1 << vcc->dev->ci_range.vci_bits usbatm_atm_init() sets ci_range.vpi_bits and ci_range.vci_bits to ATM_CI_MAX (-1), which is defined in as a sentinel value for userspace ATM_SETCIRANGE requests, not a valid bit count. Shifting by -1 is undefined behavior and triggers UBSAN warnings. ATM UNI cell headers allow up to 8 bits for VPI (0..255) and 16 bits for VCI (0..65535). Initialize vpi_bits to 8 and v",
    "evidence": "osv:CVE-2026-90055",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.270",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.221",
            "evidence": "/affected/1/ranges"
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          {
            "value": "6.1.188",
            "evidence": "/affected/1/ranges"
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          {
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            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.110",
            "evidence": "/affected/1/ranges"
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          {
            "value": "6.18.52",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-90055",
      "aliases": [
        "CVE-2026-90055"
      ],
      "affected": [
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              "type": "GIT",
              "events": [
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                  "fixed": "561cbd6d49022c9a383e22a39c87a165a4d39f9c"
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                {
                  "fixed": "76bc7c3a44856744b64aa91d9afe6d9522a78c42"
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                  "fixed": "ff7f77a234f7b74e5955a6e34fa74eca4c9ca44c"
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90055.json"
          }
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        {
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              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "2.6.13"
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                {
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90055.json"
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      ],
      "modified": "2026-10-28T02:30:37.012482066Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/1e964d414bfd9f8dfe9948d08e4b9dda4ed2e422",
        "https://git.kernel.org/stable/c/561cbd6d49022c9a383e22a39c87a165a4d39f9c",
        "https://git.kernel.org/stable/c/75667703115154a4fd9cf259d4f826d8729cbcda",
        "https://git.kernel.org/stable/c/76bc7c3a44856744b64aa91d9afe6d9522a78c42",
        "https://git.kernel.org/stable/c/7baa0c92be39eb3da755ed6f200497a57078c47b",
        "https://git.kernel.org/stable/c/8442586526c406527bf31206e538c0ce6bc672e6",
        "https://git.kernel.org/stable/c/a60fd8c6dbaa76da4163cf225ed2b9e982540f39",
        "https://git.kernel.org/stable/c/ff7f77a234f7b74e5955a6e34fa74eca4c9ca44c",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90055.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-90055",
        "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-2026-90055.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-90055",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 504413,
  "published_at": "2026-09-17T16:05:40.304+00:00"
}