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GHSA-459P-CPH9-QPFG

Vulnerability from github – Published: 2026-09-04 18:31 – Updated: 2026-09-04 18:31
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

USB: serial: option: fix slab OOB read in interrupt URB callback

The interrupt URB buffer is allocated in setup_port_interrupt_in() based on the endpoint's wMaxPacketSize:

buffer_size = usb_endpoint_maxp(epd);
port->interrupt_in_buffer = kmalloc(buffer_size, GFP_KERNEL);

When a USB device declares wMaxPacketSize = 8 on its interrupt IN endpoint, the buffer is allocated from kmalloc-8 cache (exactly 8 bytes).

If the device sends a short packet (actual_length < wMaxPacketSize), the URB completes with status == 0 and the callback proceeds to read:

data[sizeof(struct usb_ctrlrequest)]

which evaluates to data[8], accessing 1 byte beyond the allocated 8-byte buffer. This results in a slab out-of-bounds read.

Fix this by adding the missing bounds check: first verify that the actual length is large enough to contain the struct usb_ctrlrequest header before accessing req_pkt->bRequestType and req_pkt->bRequest, and then verify that there is an additional byte for the modem signal state before reading data[sizeof(struct usb_ctrlrequest)] inside the conditional. Use sizeof(*req_pkt) instead of sizeof(struct usb_ctrlrequest) for consistency.

[ johan: use dev_err(); split signals declaration and initialisation ]

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{
  "affected": [],
  "aliases": [
    "CVE-2026-80827"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-04T16:18:10Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nUSB: serial: option: fix slab OOB read in interrupt URB callback\n\nThe interrupt URB buffer is allocated in setup_port_interrupt_in() based\non the endpoint\u0027s wMaxPacketSize:\n\n    buffer_size = usb_endpoint_maxp(epd);\n    port-\u003einterrupt_in_buffer = kmalloc(buffer_size, GFP_KERNEL);\n\nWhen a USB device declares wMaxPacketSize = 8 on its interrupt IN\nendpoint, the buffer is allocated from kmalloc-8 cache (exactly\n8 bytes).\n\nIf the device sends a short packet (actual_length \u003c wMaxPacketSize),\nthe URB completes with status == 0 and the callback proceeds to read:\n\n    data[sizeof(struct usb_ctrlrequest)]\n\nwhich evaluates to data[8], accessing 1 byte beyond the allocated 8-byte\nbuffer. This results in a slab out-of-bounds read.\n\nFix this by adding the missing bounds check: first verify that the\nactual length is large enough to contain the struct usb_ctrlrequest\nheader before accessing req_pkt-\u003ebRequestType and req_pkt-\u003ebRequest,\nand then verify that there is an additional byte for the modem signal\nstate before reading data[sizeof(struct usb_ctrlrequest)] inside the\nconditional.  Use sizeof(*req_pkt) instead of sizeof(struct\nusb_ctrlrequest) for consistency.\n\n[ johan: use dev_err(); split signals declaration and initialisation ]",
  "id": "GHSA-459p-cph9-qpfg",
  "modified": "2026-09-04T18:31:28Z",
  "published": "2026-09-04T18:31:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80827"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/030e3a73d3c3aa67c44454649e984d6383cdb7d3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/060db7d48af1e650643c8b8319111a9ea2ce4486"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2ef5560387f2c0713cee975be2b24b281bd90f3e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6b8cf5422c7e96ed5b22a8368eff663f3f98b8ec"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/885d802f544ca7bfa8f3984d94233cce715bb6b3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/94e5525697b9e91ddc4071129874120a50a4f342"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a72a13c83a652516a0e469d275b81d29a7429049"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d762aef4eba354066be21a5d88eb2066e282f4c9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fbe60fd2abc8a5561f39719a41ad9a01b5d8e567"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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