{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-64257",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-07-19T15:36:31.773Z",
        "datePublished": "2026-07-25T08:49:09.345Z",
        "dateUpdated": "2026-08-17T04:52:09.787Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-17T04:52:09.787Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: reject overlapping data areas in SMB2 responses\n\nCommit 53b7c271f06b (\"smb: client: restrict implied bcc[0] exemption to\nresponses without data area\") restricted the implied bcc[0] length\nexception to responses without a data area. However, the overlap\nhandling in __smb2_calc_size() clears data_length, which can make an\ninvalid response appear to have no data area and so qualify for the\nexception.\n\nTrack data area overlap separately and reject such responses before\napplying the length compatibility exceptions."
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
                        "baseScore": 9.1,
                        "baseSeverity": "CRITICAL"
                    },
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "AV:N - A malicious or compromised SMB server can deliver the crafted SMB2 response over TCP during client negotiation.\nAC:L - The overlapping offset and oversized length are attacker-controlled and deterministically bypass validation; no race or uncontrolled memory layout is required to trigger the out-of-bounds read.\nPR:N - The vulnerable NEGOTIATE response is processed before SMB authentication or signature verification, requiring no privileges or credentials on the target.\nUI:N - An already configured SMB mount can negotiate during automatic mounting or reconnection without a human opening crafted content.\nS:U - The vulnerable parser and the affected kernel memory remain within the Linux kernel's security authority.\nC:H - The validation mismatch permits an attacker-controlled ASN.1 length to read far beyond the 448-byte receive object, potentially traversing tens of kilobytes of adjacent kernel memory.\nI:N - The investigated paths provide an out-of-bounds read but no out-of-bounds write, use-after-free, type confusion, or other arbitrary modification primitive.\nA:H - The slab out-of-bounds access is repeatable and can produce a kernel fault or panic, particularly on hardened or memory-safety-instrumented deployments."
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/smb/client/smb2misc.c"
                    ],
                    "versions": [
                        {
                            "version": "31c6312608c60b72a1feb99a5afb680645a3e8a3",
                            "lessThan": "445ece263131780dee273d727a4d6f11934feec7",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "573e502d14714d2947e22e7eff40ec20a6a44a42",
                            "lessThan": "36bfa52459e45c0d5b668de2f1c91f6dc5c67775",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "419ec1b604d7fb60c10aec2dc062371f9fcd4940",
                            "lessThan": "4a9d2657d3e05f6ed09c148cb127b4e58702275f",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "ceb875a375dedbf51c9425c1d13a2d7a8435c08c",
                            "lessThan": "fdafa1e68dc75045b7b617e6e7d2854950804d83",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "6e9d10f62773b99bd927940fd9cbdfe7207e23ff",
                            "lessThan": "57cba95f0e97c6f6e45e6731da30aff091bd7460",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "53b7c271f06be4dd5cfc8c6ef552a8355c891a7f",
                            "lessThan": "8986c932905ea508d66da421eb2eb6e676ace1fe",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "8d0bbc78046d264bbf6a574ea6f9072258a43e35",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "b6a381c01e2ac98a48e32ac0f2a45bbadd9e26b0",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "5.10.261",
                            "lessThan": "5.11",
                            "status": "affected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.15.212",
                            "lessThan": "5.16",
                            "status": "affected",
                            "versionType": "semver"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/smb/client/smb2misc.c"
                    ]
                }
            ],
            "cpeApplicability": [
                {
                    "nodes": [
                        {
                            "operator": "OR",
                            "negate": false,
                            "cpeMatch": [
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.10.261"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.15.212"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/445ece263131780dee273d727a4d6f11934feec7"
                },
                {
                    "url": "https://git.kernel.org/stable/c/36bfa52459e45c0d5b668de2f1c91f6dc5c67775"
                },
                {
                    "url": "https://git.kernel.org/stable/c/4a9d2657d3e05f6ed09c148cb127b4e58702275f"
                },
                {
                    "url": "https://git.kernel.org/stable/c/fdafa1e68dc75045b7b617e6e7d2854950804d83"
                },
                {
                    "url": "https://git.kernel.org/stable/c/57cba95f0e97c6f6e45e6731da30aff091bd7460"
                },
                {
                    "url": "https://git.kernel.org/stable/c/8986c932905ea508d66da421eb2eb6e676ace1fe"
                }
            ],
            "title": "smb: client: reject overlapping data areas in SMB2 responses",
            "x_generator": {
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}