CVE-2026-63964 (GCVE-0-2026-63964)
Vulnerability from cvelistv5
Published
2026-07-19 14:55
Modified
2026-07-20 06:41
Severity ?
Summary
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: 5c9ae5a87573d38cfc4c740aafda2fa6ce06e401
Version: 5c9ae5a87573d38cfc4c740aafda2fa6ce06e401
Version: 5c9ae5a87573d38cfc4c740aafda2fa6ce06e401
Version: 5c9ae5a87573d38cfc4c740aafda2fa6ce06e401
Version: 5c9ae5a87573d38cfc4c740aafda2fa6ce06e401
Version: 5c9ae5a87573d38cfc4c740aafda2fa6ce06e401
Version: 5c9ae5a87573d38cfc4c740aafda2fa6ce06e401
Version: 5c9ae5a87573d38cfc4c740aafda2fa6ce06e401
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/typec/ucsi/ucsi_ccg.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
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        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/typec/ucsi/ucsi_ccg.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.2"
            },
            {
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.259",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.210",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.176",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.143",
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            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.93",
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              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.35",
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              "lessThanOrEqual": "7.0.*",
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              "version": "7.0.12",
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            },
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              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "5.2",
                  "vulnerable": true
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                  "versionStartIncluding": "5.2",
                  "vulnerable": true
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                  "vulnerable": true
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                {
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                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "5.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-20T06:41:45.132Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/b41dfc033fe594e152648050e95b9489cd53e9e3"
        },
        {
          "url": "https://git.kernel.org/stable/c/2f395ca1263bd181995eb829f5943a83a20db213"
        },
        {
          "url": "https://git.kernel.org/stable/c/6526f8684f72391138353642af908803ba70795e"
        },
        {
          "url": "https://git.kernel.org/stable/c/3f432b8203066c26770fe6ea591361f10021dd6b"
        },
        {
          "url": "https://git.kernel.org/stable/c/c4ee519b06389e59ba2d6aa722fcc4a02a8bbcbb"
        },
        {
          "url": "https://git.kernel.org/stable/c/a38ed87818b2419090fb1a6338ddce6842b65dfa"
        },
        {
          "url": "https://git.kernel.org/stable/c/c8460de584fe5415d212cfdd127d4db90835a450"
        },
        {
          "url": "https://git.kernel.org/stable/c/d7486952bf74e546ee3748fb14b2d07881fa6273"
        }
      ],
      "title": "usb: typec: ucsi: ccg: reject firmware images without a \u0027:\u0027 record header",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63964",
    "datePublished": "2026-07-19T14:55:53.115Z",
    "dateReserved": "2026-07-19T07:54:57.024Z",
    "dateUpdated": "2026-07-20T06:41:45.132Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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