CVE-2026-90055

Full vulnerability record from the local CVENow database.

Description

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: <TASK> 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 <uapi/linux/atmdev.h> 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 vci_bits to 16, as done by solos-pci.

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-09-17 17:16:54.020000

Last modified

2026-10-19 09:18:53.783000

View original CVE JSON

{
  "id": "CVE-2026-90055",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-09-17T17:16:54.020",
  "lastModified": "2026-10-19T09:18:53.783",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: atm: usbatm: fix invalid ci_range initialization\n\nsyzbot reported a shift-out-of-bounds in __vcc_connect():\n\n  UBSAN: shift-out-of-bounds in net/atm/common.c:382:32\n  shift exponent -1 is negative\n  CPU: 0 UID: 0 PID: 5987 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(full)\n  Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026\n  Call Trace:\n   <TASK>\n   dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120\n   ubsan_epilogue+0xa/0x30 lib/ubsan.c:233\n   __ubsan_handle_shift_out_of_bounds+0x36d/0x400 lib/ubsan.c:494\n   __vcc_connect+0x14b4/0x19c0 net/atm/common.c:382\n   vcc_connect+0x328/0x8f0 net/atm/common.c:498\n   pvc_bind+0x272/0x380 net/atm/pvc.c:52\n   __sys_bind+0x2e3/0x410 net/socket.c:1976\n   __x64_sys_bind+0x7a/0x90 net/socket.c:1979\n   ...\n\nATM device ci_range fields (vpi_bits and vci_bits) represent the\nnumber of bits supported for VPI and VCI addressing on the device.\nnet/atm/common.c directly uses these fields as bit shift counts:\n  vpi >> dev->ci_range.vpi_bits\n  vci >> dev->ci_range.vci_bits\n  1 << vcc->dev->ci_range.vpi_bits\n  1 << vcc->dev->ci_range.vci_bits\n\nusbatm_atm_init() sets ci_range.vpi_bits and ci_range.vci_bits to\nATM_CI_MAX (-1), which is defined in <uapi/linux/atmdev.h> as a\nsentinel value for userspace ATM_SETCIRANGE requests, not a valid bit\ncount. Shifting by -1 is undefined behavior and triggers UBSAN\nwarnings.\n\nATM UNI cell headers allow up to 8 bits for VPI (0..255) and 16 bits\nfor VCI (0..65535). Initialize vpi_bits to 8 and vci_bits to 16, as\ndone by solos-pci."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "drivers/usb/atm/usbatm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "c59bba75fa500f13ef14215d599ee0d7faa1b954",
              "lessThan": "8442586526c406527bf31206e538c0ce6bc672e6",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "c59bba75fa500f13ef14215d599ee0d7faa1b954",
              "lessThan": "561cbd6d49022c9a383e22a39c87a165a4d39f9c",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "c59bba75fa500f13ef14215d599ee0d7faa1b954",
              "lessThan": "76bc7c3a44856744b64aa91d9afe6d9522a78c42",
              "versionType": "git",
              "status": "affected"
            },
            {
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              "versionType": "git",
              "status": "affected"
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            {
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              "lessThan": "1e964d414bfd9f8dfe9948d08e4b9dda4ed2e422",
              "versionType": "git",
              "status": "affected"
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            {
              "version": "c59bba75fa500f13ef14215d599ee0d7faa1b954",
              "lessThan": "ff7f77a234f7b74e5955a6e34fa74eca4c9ca44c",
              "versionType": "git",
              "status": "affected"
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            {
              "version": "c59bba75fa500f13ef14215d599ee0d7faa1b954",
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              "versionType": "git",
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              "versionType": "git",
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        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "drivers/usb/atm/usbatm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "2.6.13",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "2.6.13",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.10.270",
              "lessThanOrEqual": "5.10.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.15.221",
              "lessThanOrEqual": "5.15.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.1.188",
              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.157",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.110",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.52",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.6",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1e964d414bfd9f8dfe9948d08e4b9dda4ed2e422",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/561cbd6d49022c9a383e22a39c87a165a4d39f9c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/75667703115154a4fd9cf259d4f826d8729cbcda",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8442586526c406527bf31206e538c0ce6bc672e6",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}