{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-64391",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-07-19T15:36:31.785Z",
        "datePublished": "2026-07-25T08:50:38.013Z",
        "dateUpdated": "2026-08-17T04:54:43.832Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-17T04:54:43.832Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: use opener credentials for ADS I/O\n\nAlternate data streams are stored as xattrs. Unlike regular file I/O,\ntheir read and write paths therefore call VFS xattr helpers which recheck\ninode permissions and LSM policy using the current task credentials.\n\nRun ADS I/O with the credentials captured when the SMB handle was opened."
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                        "baseScore": 9.8,
                        "baseSeverity": "CRITICAL"
                    },
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "AV:N - An attacker reaches the vulnerable ADS read and write paths through SMB2 requests to an exposed ksmbd server over TCP/445.\nAC:L - Exploitation is deterministic using an ADS handle followed by ordinary SMB2 READ or WRITE requests; no race, memory-layout dependency, or condition outside the attacker's control is required.\nPR:N - Although a valid session, tree connection, and handle are required, a guest-enabled streams share permits a remote client to establish the necessary guest session without supplying valid credentials.\nUI:N - The attacker directly opens and accesses the alternate data stream through SMB requests without requiring any victim action.\nS:U - The credential bypass affects ADS data managed by the same host kernel and filesystem security authority; it does not cross a virtualization or comparable isolation boundary.\nC:H - Privileged worker credentials can bypass inode and LSM xattr checks and disclose the complete contents of an attacker-selected named stream, including potentially sensitive application data.\nI:H - The vulnerable write path can bypass xattr authorization and replace or truncate the complete named stream with attacker-controlled data.\nA:H - Repeated unauthorized truncation or corruption can persistently destroy an ADS and render applications or services that depend on that stream unusable until the data is restored."
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/smb/server/vfs.c"
                    ],
                    "versions": [
                        {
                            "version": "f44158485826c076335d6860d35872271a83791d",
                            "lessThan": "a8f5d39971bbad9340d49cd41b0e2da9452a649d",
                            "status": "affected",
                            "versionType": "git"
                        },
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                            "version": "f44158485826c076335d6860d35872271a83791d",
                            "lessThan": "2b4592cea214683de0f2ce6f8c22c097fb0ea1ab",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "f44158485826c076335d6860d35872271a83791d",
                            "lessThan": "52a56cf53ec834c44ac1b4d16d585f26613ee5ce",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "f44158485826c076335d6860d35872271a83791d",
                            "lessThan": "baa5e094886fffa7e6272edcb5e08be5ce28262c",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/smb/server/vfs.c"
                    ],
                    "versions": [
                        {
                            "version": "5.15",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "5.15",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.96",
                            "lessThanOrEqual": "6.12.*",
                            "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": "5.15",
                                    "versionEndExcluding": "6.12.96"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.15",
                                    "versionEndExcluding": "6.18.39"
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                                    "versionStartIncluding": "5.15",
                                    "versionEndExcluding": "7.1.4"
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                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.15",
                                    "versionEndExcluding": "7.2"
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            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/a8f5d39971bbad9340d49cd41b0e2da9452a649d"
                },
                {
                    "url": "https://git.kernel.org/stable/c/2b4592cea214683de0f2ce6f8c22c097fb0ea1ab"
                },
                {
                    "url": "https://git.kernel.org/stable/c/52a56cf53ec834c44ac1b4d16d585f26613ee5ce"
                },
                {
                    "url": "https://git.kernel.org/stable/c/baa5e094886fffa7e6272edcb5e08be5ce28262c"
                }
            ],
            "title": "ksmbd: use opener credentials for ADS I/O",
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}