{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-64339",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-07-19T15:36:31.781Z",
        "datePublished": "2026-07-25T08:50:03.272Z",
        "dateUpdated": "2026-08-17T04:53:42.778Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-17T04:53:42.778Z"
            },
            "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->len) bytes out of\nthe bulk IN buffer (usbio->rxbuf, allocated with size usbio->rxbuf_len)\ninto the caller's buffer.  bpkt_len is fully controlled by the device\nand is only checked against ibuf_len; ibuf_len in turn is checked\nagainst usbio->txbuf_len, not against rxbuf_len:\n\n\tif ((obuf_len > (usbio->txbuf_len - sizeof(*bpkt))) ||\n\t    (ibuf_len > (usbio->txbuf_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 < 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()'s\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": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "drivers/usb/misc/usbio.c"
                    ],
                    "versions": [
                        {
                            "version": "121a0f839dbb397af5fabb701cea3e9983223e50",
                            "lessThan": "48394f94211cf8fe0ea8604fc441633abf90fc94",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "121a0f839dbb397af5fabb701cea3e9983223e50",
                            "lessThan": "fc1b546973c1442d5b947fcdd03581f20ecc5bd2",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "121a0f839dbb397af5fabb701cea3e9983223e50",
                            "lessThan": "8c6314489550fa81d41723a0ff33f655b5b6c7b6",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "drivers/usb/misc/usbio.c"
                    ],
                    "versions": [
                        {
                            "version": "6.18",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "6.18",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.39",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.1.4",
                            "lessThanOrEqual": "7.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }
            ],
            "cpeApplicability": [
                {
                    "nodes": [
                        {
                            "operator": "OR",
                            "negate": false,
                            "cpeMatch": [
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.18",
                                    "versionEndExcluding": "6.18.39"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.18",
                                    "versionEndExcluding": "7.1.4"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.18",
                                    "versionEndExcluding": "7.2"
                                }
                            ]
                        }
                    ]
                }
            ],
            "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"
            }
        }
    }
}