CVE-2026-64339 (GCVE-0-2026-64339)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:50 – Updated: 2026-07-25 08:50
VLAI
Title
usb: misc: usbio: bound bulk IN response length to the received transfer
Summary
In the Linux kernel, the following vulnerability has been resolved: usb: misc: usbio: bound bulk IN response length to the received transfer usbio_bulk_msg() copies bpkt_len = le16_to_cpu(bpkt->len) bytes out of the bulk IN buffer (usbio->rxbuf, allocated with size usbio->rxbuf_len) into the caller's buffer. bpkt_len is fully controlled by the device and is only checked against ibuf_len; ibuf_len in turn is checked against usbio->txbuf_len, not against rxbuf_len: if ((obuf_len > (usbio->txbuf_len - sizeof(*bpkt))) || (ibuf_len > (usbio->txbuf_len - sizeof(*bpkt)))) return -EMSGSIZE; txbuf_len and rxbuf_len are taken independently from the bulk OUT and bulk IN endpoint wMaxPacketSize in usbio_probe(). A malicious or malfunctioning device that advertises a large bulk OUT endpoint and a small bulk IN endpoint (e.g. by claiming one of the quirk-free IDs such as the Lattice NX33U, 0x2ac1:0x20cb) therefore makes ibuf_len, and hence the device-supplied bpkt_len, exceed rxbuf_len. memcpy() then reads up to txbuf_len - rxbuf_len bytes past the end of the rxbuf slab object. The over-read bytes are handed back to the i2c layer and on to user space through i2c-dev, disclosing adjacent slab memory; with KASAN this is reported as a slab-out-of-bounds read. The number of bytes actually received is already known: act equals the URB actual_length and is bounded by rxbuf_len. Reject any response that claims more payload than was received, mirroring the existing "act < sizeof(*bpkt)" check just above. The control path (usbio_ctrl_msg()) is not affected: it uses a single buffer (ctrlbuf) for both directions, so its analogous copy can never leave the allocation. Found by code review. The out-of-bounds read was confirmed under AddressSanitizer with a faithful userspace model of usbio_bulk_msg()'s receive path (an rxbuf_len-sized buffer, the same act/ibuf_len/bpkt_len checks and the memcpy). A USB raw-gadget + dummy_hcd reproducer is also available.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 121a0f839dbb397af5fabb701cea3e9983223e50 , < 48394f94211cf8fe0ea8604fc441633abf90fc94 (git)
Affected: 121a0f839dbb397af5fabb701cea3e9983223e50 , < fc1b546973c1442d5b947fcdd03581f20ecc5bd2 (git)
Affected: 121a0f839dbb397af5fabb701cea3e9983223e50 , < 8c6314489550fa81d41723a0ff33f655b5b6c7b6 (git)
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Linux Linux Affected: 6.18
Unaffected: 0 , < 6.18 (semver)
Unaffected: 6.18.39 , ≤ 6.18.* (semver)
Unaffected: 7.1.4 , ≤ 7.1.* (semver)
Unaffected: 7.2-rc3 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/misc/usbio.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "48394f94211cf8fe0ea8604fc441633abf90fc94",
              "status": "affected",
              "version": "121a0f839dbb397af5fabb701cea3e9983223e50",
              "versionType": "git"
            },
            {
              "lessThan": "fc1b546973c1442d5b947fcdd03581f20ecc5bd2",
              "status": "affected",
              "version": "121a0f839dbb397af5fabb701cea3e9983223e50",
              "versionType": "git"
            },
            {
              "lessThan": "8c6314489550fa81d41723a0ff33f655b5b6c7b6",
              "status": "affected",
              "version": "121a0f839dbb397af5fabb701cea3e9983223e50",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/misc/usbio.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "lessThan": "6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.39",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.4",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2-rc3",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: misc: usbio: bound bulk IN response length to the received transfer\n\nusbio_bulk_msg() copies bpkt_len = le16_to_cpu(bpkt-\u003elen) bytes out of\nthe bulk IN buffer (usbio-\u003erxbuf, allocated with size usbio-\u003erxbuf_len)\ninto the caller\u0027s buffer.  bpkt_len is fully controlled by the device\nand is only checked against ibuf_len; ibuf_len in turn is checked\nagainst usbio-\u003etxbuf_len, not against rxbuf_len:\n\n\tif ((obuf_len \u003e (usbio-\u003etxbuf_len - sizeof(*bpkt))) ||\n\t    (ibuf_len \u003e (usbio-\u003etxbuf_len - sizeof(*bpkt))))\n\t\treturn -EMSGSIZE;\n\ntxbuf_len and rxbuf_len are taken independently from the bulk OUT and\nbulk IN endpoint wMaxPacketSize in usbio_probe().  A malicious or\nmalfunctioning device that advertises a large bulk OUT endpoint and a\nsmall bulk IN endpoint (e.g. by claiming one of the quirk-free IDs such\nas the Lattice NX33U, 0x2ac1:0x20cb) therefore makes ibuf_len, and\nhence the device-supplied bpkt_len, exceed rxbuf_len.  memcpy() then\nreads up to txbuf_len - rxbuf_len bytes past the end of the rxbuf slab\nobject.  The over-read bytes are handed back to the i2c layer and on to\nuser space through i2c-dev, disclosing adjacent slab memory; with KASAN\nthis is reported as a slab-out-of-bounds read.\n\nThe number of bytes actually received is already known: act equals the\nURB actual_length and is bounded by rxbuf_len.  Reject any response\nthat claims more payload than was received, mirroring the existing\n\"act \u003c sizeof(*bpkt)\" check just above.\n\nThe control path (usbio_ctrl_msg()) is not affected: it uses a single\nbuffer (ctrlbuf) for both directions, so its analogous copy can never\nleave the allocation.\n\nFound by code review.  The out-of-bounds read was confirmed under\nAddressSanitizer with a faithful userspace model of usbio_bulk_msg()\u0027s\nreceive path (an rxbuf_len-sized buffer, the same act/ibuf_len/bpkt_len\nchecks and the memcpy).  A USB raw-gadget + dummy_hcd reproducer is\nalso available."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-25T08:50:03.272Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/48394f94211cf8fe0ea8604fc441633abf90fc94"
        },
        {
          "url": "https://git.kernel.org/stable/c/fc1b546973c1442d5b947fcdd03581f20ecc5bd2"
        },
        {
          "url": "https://git.kernel.org/stable/c/8c6314489550fa81d41723a0ff33f655b5b6c7b6"
        }
      ],
      "title": "usb: misc: usbio: bound bulk IN response length to the received transfer",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64339",
    "datePublished": "2026-07-25T08:50:03.272Z",
    "dateReserved": "2026-07-19T15:36:31.781Z",
    "dateUpdated": "2026-07-25T08:50:03.272Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-64339",
      "date": "2026-07-27",
      "epss": "0.00198",
      "percentile": "0.09843"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-64339\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-07-25T10:17:15.870\",\"lastModified\":\"2026-07-25T10:17:15.870\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nusb: misc: usbio: bound bulk IN response length to the received transfer\\n\\nusbio_bulk_msg() copies bpkt_len = le16_to_cpu(bpkt-\u003elen) bytes out of\\nthe bulk IN buffer (usbio-\u003erxbuf, allocated with size usbio-\u003erxbuf_len)\\ninto the caller\u0027s buffer.  bpkt_len is fully controlled by the device\\nand is only checked against ibuf_len; ibuf_len in turn is checked\\nagainst usbio-\u003etxbuf_len, not against rxbuf_len:\\n\\n\\tif ((obuf_len \u003e (usbio-\u003etxbuf_len - sizeof(*bpkt))) ||\\n\\t    (ibuf_len \u003e (usbio-\u003etxbuf_len - sizeof(*bpkt))))\\n\\t\\treturn -EMSGSIZE;\\n\\ntxbuf_len and rxbuf_len are taken independently from the bulk OUT and\\nbulk IN endpoint wMaxPacketSize in usbio_probe().  A malicious or\\nmalfunctioning device that advertises a large bulk OUT endpoint and a\\nsmall bulk IN endpoint (e.g. by claiming one of the quirk-free IDs such\\nas the Lattice NX33U, 0x2ac1:0x20cb) therefore makes ibuf_len, and\\nhence the device-supplied bpkt_len, exceed rxbuf_len.  memcpy() then\\nreads up to txbuf_len - rxbuf_len bytes past the end of the rxbuf slab\\nobject.  The over-read bytes are handed back to the i2c layer and on to\\nuser space through i2c-dev, disclosing adjacent slab memory; with KASAN\\nthis is reported as a slab-out-of-bounds read.\\n\\nThe number of bytes actually received is already known: act equals the\\nURB actual_length and is bounded by rxbuf_len.  Reject any response\\nthat claims more payload than was received, mirroring the existing\\n\\\"act \u003c sizeof(*bpkt)\\\" check just above.\\n\\nThe control path (usbio_ctrl_msg()) is not affected: it uses a single\\nbuffer (ctrlbuf) for both directions, so its analogous copy can never\\nleave the allocation.\\n\\nFound by code review.  The out-of-bounds read was confirmed under\\nAddressSanitizer with a faithful userspace model of usbio_bulk_msg()\u0027s\\nreceive path (an rxbuf_len-sized buffer, the same act/ibuf_len/bpkt_len\\nchecks and the memcpy).  A USB raw-gadget + dummy_hcd reproducer is\\nalso available.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/usb/misc/usbio.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"121a0f839dbb397af5fabb701cea3e9983223e50\",\"lessThan\":\"48394f94211cf8fe0ea8604fc441633abf90fc94\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"121a0f839dbb397af5fabb701cea3e9983223e50\",\"lessThan\":\"fc1b546973c1442d5b947fcdd03581f20ecc5bd2\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"121a0f839dbb397af5fabb701cea3e9983223e50\",\"lessThan\":\"8c6314489550fa81d41723a0ff33f655b5b6c7b6\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/usb/misc/usbio.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.18\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.18\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.39\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.4\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2-rc3\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/48394f94211cf8fe0ea8604fc441633abf90fc94\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/8c6314489550fa81d41723a0ff33f655b5b6c7b6\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/fc1b546973c1442d5b947fcdd03581f20ecc5bd2\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "suse_vex": {
      "aggregate_severity": "not set",
      "current_release_date": "2026-07-25T16:01:29Z",
      "cve": "CVE-2026-64339",
      "id": "CVE-2026-64339",
      "initial_release_date": "2026-07-25T16:01:29Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64339",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64339.json",
      "version": "2"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.