GHSA-7W55-P3P4-26MV

Vulnerability from github – Published: 2026-07-19 18:31 – Updated: 2026-07-19 18:31
VLAI
Details

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

usb: typec: ucsi: ccg: reject firmware images without a ':' record header

do_flash() locates the first .cyacd record with

p = strnchr(fw->data, fw->size, ':');
while (p < eof) {
    s = strnchr(p + 1, eof - p - 1, ':');
    ...
}

If the firmware image contains no ':' byte, strnchr() returns NULL. NULL compares less than the valid kernel pointer eof, so the loop body runs and strnchr() is called with p + 1 == (void *)1 and a length of roughly (unsigned long)eof, causing a wonderful crash.

The not_signed_fw fallthrough earlier in do_flash() and the chip-state branches in ccg_fw_update_needed() allow an unsigned blob to reach this loop, so a root user who can place a crafted file under /lib/firmware and write the do_flash sysfs attribute can trigger the oops.

Bail out with -EINVAL when the initial strnchr() returns NULL.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-63964"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-19T16:17:15Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: typec: ucsi: ccg: reject firmware images without a \u0027:\u0027 record header\n\ndo_flash() locates the first .cyacd record with\n\n\tp = strnchr(fw-\u003edata, fw-\u003esize, \u0027:\u0027);\n\twhile (p \u003c eof) {\n\t\ts = strnchr(p + 1, eof - p - 1, \u0027:\u0027);\n\t\t...\n\t}\n\nIf the firmware image contains no \u0027:\u0027 byte,  strnchr() returns NULL.\nNULL compares less than the valid kernel pointer eof, so the loop body\nruns and strnchr() is called with p + 1 == (void *)1 and a length of\nroughly (unsigned long)eof, causing a wonderful crash.\n\nThe not_signed_fw fallthrough earlier in do_flash() and the chip-state\nbranches in ccg_fw_update_needed() allow an unsigned blob to reach this\nloop, so a root user who can place a crafted file under /lib/firmware\nand write the do_flash sysfs attribute can trigger the oops.\n\nBail out with -EINVAL when the initial strnchr() returns NULL.",
  "id": "GHSA-7w55-p3p4-26mv",
  "modified": "2026-07-19T18:31:48Z",
  "published": "2026-07-19T18:31:47Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63964"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2f395ca1263bd181995eb829f5943a83a20db213"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3f432b8203066c26770fe6ea591361f10021dd6b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6526f8684f72391138353642af908803ba70795e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a38ed87818b2419090fb1a6338ddce6842b65dfa"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b41dfc033fe594e152648050e95b9489cd53e9e3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c4ee519b06389e59ba2d6aa722fcc4a02a8bbcbb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c8460de584fe5415d212cfdd127d4db90835a450"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d7486952bf74e546ee3748fb14b2d07881fa6273"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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