{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-99040",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-09-25T10:25:14.387Z",
        "datePublished": "2026-10-23T12:21:59.288Z",
        "dateUpdated": "2026-10-30T12:41:13.694Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-10-30T12:41:13.694Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKEYS: Fix add_key() race with keyring restriction\n\n__key_create_or_update() snapshots keyring->restrict_link before taking\nthe destination keyring's semaphore.  keyring_restrict() installs a\nrestriction while holding that semaphore.\n\nThis allows a writer to observe no restriction, wait for the keyring\nowner to install a reject-all restriction and return successfully, and\nthen link a key using the stale NULL snapshot.  The writer only needs\nwrite permission on the destination keyring.\n\nMove the restrict_link read after __key_link_lock() and\n__key_link_begin().  The read and the subsequent restriction check are\nthen serialized with restriction installation by keyring->sem.\n\nThe race was reproduced on v7.2.8 in 19 executions where restriction\ninstallation returned before the link completed.  All 19 linked the key\ndespite the reject-all restriction.  With this change, 312 executions\nreached the same ordering and every add_key() call failed with -EPERM.\n\nThe issue was found by manual concurrency analysis assisted by AI-based\nanalysis and independently verified with a QEMU reproducer and kernel\ninstrumentation."
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "security/keys/key.c"
                    ],
                    "versions": [
                        {
                            "version": "5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c",
                            "lessThan": "24806fc9bca28fa1433bf938d1424dcb45d80e50",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c",
                            "lessThan": "9a5c2700336878465a630804a2d21864f22eca9c",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c",
                            "lessThan": "b3e404550dc2b7f3d4bb64b1da8005a1fa9a798d",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c",
                            "lessThan": "305f1828b871dd46bf41addeb6f11d2c162dcb25",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c",
                            "lessThan": "f99399b48e3edd6851fac34cd329bab9f1f33baf",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c",
                            "lessThan": "11516a0c402a6c1fa52254aa70d8d65fb921e59e",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c",
                            "lessThan": "da0b595d8e6e2dd798f6e34e09dc51a13b888514",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c",
                            "lessThan": "dd3ea3fcba7c75493760cdbccd35f029597e8d5e",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "security/keys/key.c"
                    ],
                    "versions": [
                        {
                            "version": "4.7",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "4.7",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.10.273",
                            "lessThanOrEqual": "5.10.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.15.224",
                            "lessThanOrEqual": "5.15.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.1.191",
                            "lessThanOrEqual": "6.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.160",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.113",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.57",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2.11",
                            "lessThanOrEqual": "7.2.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.3",
                            "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": "4.7",
                                    "versionEndExcluding": "5.10.273"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.7",
                                    "versionEndExcluding": "5.15.224"
                                },
                                {
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                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                                    "versionEndExcluding": "7.2.11"
                                },
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                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.7",
                                    "versionEndExcluding": "7.3"
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            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/24806fc9bca28fa1433bf938d1424dcb45d80e50"
                },
                {
                    "url": "https://git.kernel.org/stable/c/9a5c2700336878465a630804a2d21864f22eca9c"
                },
                {
                    "url": "https://git.kernel.org/stable/c/b3e404550dc2b7f3d4bb64b1da8005a1fa9a798d"
                },
                {
                    "url": "https://git.kernel.org/stable/c/305f1828b871dd46bf41addeb6f11d2c162dcb25"
                },
                {
                    "url": "https://git.kernel.org/stable/c/f99399b48e3edd6851fac34cd329bab9f1f33baf"
                },
                {
                    "url": "https://git.kernel.org/stable/c/11516a0c402a6c1fa52254aa70d8d65fb921e59e"
                },
                {
                    "url": "https://git.kernel.org/stable/c/da0b595d8e6e2dd798f6e34e09dc51a13b888514"
                },
                {
                    "url": "https://git.kernel.org/stable/c/dd3ea3fcba7c75493760cdbccd35f029597e8d5e"
                }
            ],
            "title": "KEYS: Fix add_key() race with keyring restriction",
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    }
}