{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2021-47646",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2025-02-26T01:48:21.520Z",
        "datePublished": "2025-02-26T01:54:15.122Z",
        "dateUpdated": "2026-05-11T13:58:29.013Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-05-11T13:58:29.013Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRevert \"Revert \"block, bfq: honor already-setup queue merges\"\"\n\nA crash [1] happened to be triggered in conjunction with commit\n2d52c58b9c9b (\"block, bfq: honor already-setup queue merges\"). The\nlatter was then reverted by commit ebc69e897e17 (\"Revert \"block, bfq:\nhonor already-setup queue merges\"\"). Yet, the reverted commit was not\nthe one introducing the bug. In fact, it actually triggered a UAF\nintroduced by a different commit, and now fixed by commit d29bd41428cf\n(\"block, bfq: reset last_bfqq_created on group change\").\n\nSo, there is no point in keeping commit 2d52c58b9c9b (\"block, bfq:\nhonor already-setup queue merges\") out. This commit restores it.\n\n[1] https://bugzilla.kernel.org/show_bug.cgi?id=214503"
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "block/bfq-iosched.c"
                    ],
                    "versions": [
                        {
                            "version": "aee69d78dec0ffdf82e35d57c626e80dddc314d5",
                            "lessThan": "f990f0985eda59d4f29fc83fcf300c92b1225d39",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "aee69d78dec0ffdf82e35d57c626e80dddc314d5",
                            "lessThan": "931aff627469a75c77b9fd3823146d0575afffd6",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "aee69d78dec0ffdf82e35d57c626e80dddc314d5",
                            "lessThan": "cc051f497eac9d8a0d816cd4bffa3415f2724871",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "aee69d78dec0ffdf82e35d57c626e80dddc314d5",
                            "lessThan": "65d8a737452e88f251fe5d925371de6d606df613",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "aee69d78dec0ffdf82e35d57c626e80dddc314d5",
                            "lessThan": "abc2129e646af7b43025d90a071f83043f1ae76c",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "aee69d78dec0ffdf82e35d57c626e80dddc314d5",
                            "lessThan": "4083925bd6dc89216d156474a8076feec904e607",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "aee69d78dec0ffdf82e35d57c626e80dddc314d5",
                            "lessThan": "15729ff8143f8135b03988a100a19e66d7cb7ecd",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "block/bfq-iosched.c"
                    ],
                    "versions": [
                        {
                            "version": "4.12",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "4.12",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "4.19.238",
                            "lessThanOrEqual": "4.19.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.4.189",
                            "lessThanOrEqual": "5.4.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.10.110",
                            "lessThanOrEqual": "5.10.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.15.33",
                            "lessThanOrEqual": "5.15.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.16.19",
                            "lessThanOrEqual": "5.16.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.17.2",
                            "lessThanOrEqual": "5.17.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.18",
                            "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": "4.12",
                                    "versionEndExcluding": "4.19.238"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.12",
                                    "versionEndExcluding": "5.4.189"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.12",
                                    "versionEndExcluding": "5.10.110"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.12",
                                    "versionEndExcluding": "5.15.33"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.12",
                                    "versionEndExcluding": "5.16.19"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.12",
                                    "versionEndExcluding": "5.17.2"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.12",
                                    "versionEndExcluding": "5.18"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/f990f0985eda59d4f29fc83fcf300c92b1225d39"
                },
                {
                    "url": "https://git.kernel.org/stable/c/931aff627469a75c77b9fd3823146d0575afffd6"
                },
                {
                    "url": "https://git.kernel.org/stable/c/cc051f497eac9d8a0d816cd4bffa3415f2724871"
                },
                {
                    "url": "https://git.kernel.org/stable/c/65d8a737452e88f251fe5d925371de6d606df613"
                },
                {
                    "url": "https://git.kernel.org/stable/c/abc2129e646af7b43025d90a071f83043f1ae76c"
                },
                {
                    "url": "https://git.kernel.org/stable/c/4083925bd6dc89216d156474a8076feec904e607"
                },
                {
                    "url": "https://git.kernel.org/stable/c/15729ff8143f8135b03988a100a19e66d7cb7ecd"
                }
            ],
            "title": "Revert \"Revert \"block, bfq: honor already-setup queue merges\"\"",
            "x_generator": {
                "engine": "bippy-1.2.0"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "cvssV3_1": {
                            "scope": "UNCHANGED",
                            "version": "3.1",
                            "baseScore": 7.8,
                            "attackVector": "LOCAL",
                            "baseSeverity": "HIGH",
                            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                            "integrityImpact": "HIGH",
                            "userInteraction": "NONE",
                            "attackComplexity": "LOW",
                            "availabilityImpact": "HIGH",
                            "privilegesRequired": "LOW",
                            "confidentialityImpact": "HIGH"
                        }
                    },
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "id": "CVE-2021-47646",
                                "role": "CISA Coordinator",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "total"
                                    }
                                ],
                                "version": "2.0.3",
                                "timestamp": "2025-02-27T17:59:39.194997Z"
                            }
                        }
                    }
                ],
                "problemTypes": [
                    {
                        "descriptions": [
                            {
                                "lang": "en",
                                "type": "CWE",
                                "cweId": "CWE-416",
                                "description": "CWE-416 Use After Free"
                            }
                        ]
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2025-02-27T18:02:30.637Z"
                }
            }
        ]
    }
}