{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-68166",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-07-30T09:28:09.372Z",
        "datePublished": "2026-08-10T11:59:34.576Z",
        "dateUpdated": "2026-08-23T12:46:02.309Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-23T12:46:02.309Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nuserfaultfd: prevent registration of special VMAs\n\nVova Tokarev says:\n\n  userfaultfd allows registration on shadow stack VMAs.  With userfaultfd\n  access, you can register on the shadow stack, discard a page ... and\n  inject a page with chosen return addresses via UFFDIO_COPY.\n\nUpdate vma_can_userfault() to reject VM_SHADOW_STACK.\n\nWhile on it, also reject VM_SPECIAL so that if a driver would implement\nvm_uffd_ops, it wouldn't be possible to register special VMAs with\nuserfaultfd.\n\nSince VM_SPECIAL includes VM_DONTEXPAND which is set but hugetlb, exclude\nhugetlb VMAs from the check for VM_SPECIAL."
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "mm/userfaultfd.c"
                    ],
                    "versions": [
                        {
                            "version": "54007f818206dc27309ca423df4c87dd160a7208",
                            "lessThan": "d974b4b786214883bd8e56bda10b454c80fd6205",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "54007f818206dc27309ca423df4c87dd160a7208",
                            "lessThan": "495a28d5a100be1b232633f4c2dcc42ba10b3796",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "54007f818206dc27309ca423df4c87dd160a7208",
                            "lessThan": "165613191ad9d034bf17c00e3a142f9561597ec5",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "54007f818206dc27309ca423df4c87dd160a7208",
                            "lessThan": "0c26202b157f1efc3cd2f26f5c30f59b508a6a5d",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "54007f818206dc27309ca423df4c87dd160a7208",
                            "lessThan": "3c58f641e813c3c71039f8fd4d4e2a3aab713288",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "mm/userfaultfd.c"
                    ],
                    "versions": [
                        {
                            "version": "6.6",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "6.6",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.153",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.105",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.44",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.1.6",
                            "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": "6.6",
                                    "versionEndExcluding": "6.6.153"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.6",
                                    "versionEndExcluding": "6.12.105"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.6",
                                    "versionEndExcluding": "6.18.44"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.6",
                                    "versionEndExcluding": "7.1.6"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.6",
                                    "versionEndExcluding": "7.2"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/d974b4b786214883bd8e56bda10b454c80fd6205"
                },
                {
                    "url": "https://git.kernel.org/stable/c/495a28d5a100be1b232633f4c2dcc42ba10b3796"
                },
                {
                    "url": "https://git.kernel.org/stable/c/165613191ad9d034bf17c00e3a142f9561597ec5"
                },
                {
                    "url": "https://git.kernel.org/stable/c/0c26202b157f1efc3cd2f26f5c30f59b508a6a5d"
                },
                {
                    "url": "https://git.kernel.org/stable/c/3c58f641e813c3c71039f8fd4d4e2a3aab713288"
                }
            ],
            "title": "userfaultfd: prevent registration of special VMAs",
            "x_generator": {
                "engine": "bippy-1.2.0"
            }
        }
    }
}