smb: client: fix OOB read in smb2_ioctl_query_info QUERY_INFO path_CVE-2026-31708

{
    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix OOB read in smb2_ioctl_query_info QUERY_INFO path\n\nsmb2_ioctl_query_info() has two response-copy branches: PASSTHRU_FSCTL\nand the default QUERY_INFO path.  The QUERY_INFO branch clamps\nqi.input_buffer_length to the server-reported OutputBufferLength and then\ncopies qi.input_buffer_length bytes from qi_rsp->Buffer to userspace, but\nit never verifies that the flexible-array payload actually fits within\nrsp_iov[1].iov_len.\n\nA malicious server can return OutputBufferLength larger than the actual\nQUERY_INFO response, causing copy_to_user() to walk past the response\nbuffer and expose adjacent kernel heap to userspace.\n\nGuard the QUERY_INFO copy with a bounds check on the actual Buffer\npayload.  Use struct_size(qi_rsp, Buffer, qi.input_buffer_length)\nrather than an open-coded addition so the guard cannot overflow on\n32-bit builds.",
    "published": "2026-05-01T13:56:05.880Z",
    "modified": "2026-05-03T05:45:31.965Z",
    "type": "cve",
    "title": "smb: client: fix OOB read in smb2_ioctl_query_info QUERY_INFO path",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/a34d456934fe42e4da5d2cc07787bf418bee99c6\nhttps://git.kernel.org/stable/c/ac2f14e4705d020f04e806efa0d49ab8dc2b145f\nhttps://git.kernel.org/stable/c/078fae8f50adebb903ccf2252b44391324571e78\nhttps://git.kernel.org/stable/c/85fd46ee26a11841c670449508025965f61ce131\nhttps://git.kernel.org/stable/c/a58c5af19ff0d6f44f6e9fe31e33a2c92223f77e",
    "id": "CVE-2026-31708",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux f5778c398713692a16150ae96e5c8270bab8399f\nLinux Linux f5778c398713692a16150ae96e5c8270bab8399f\nLinux Linux f5778c398713692a16150ae96e5c8270bab8399f\nLinux Linux f5778c398713692a16150ae96e5c8270bab8399f\nLinux Linux f5778c398713692a16150ae96e5c8270bab8399f\nLinux Linux 5.1",
    "sourceHref": "",
    "cvss": {
        "score": 8.1,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "f5778c398713692a16150ae96e5c8270bab8399f",
    "vendor": "Linux",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}