{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2023-54227",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2025-12-30T12:06:44.502Z",
        "datePublished": "2025-12-30T12:11:20.207Z",
        "dateUpdated": "2026-08-05T09:18:13.008Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-05T09:18:13.008Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblk-mq: fix tags leak when shrink nr_hw_queues\n\nAlthough we don't need to realloc set->tags[] when shrink nr_hw_queues,\nwe need to free them. Or these tags will be leaked.\n\nHow to reproduce:\n1. mount -t configfs configfs /mnt\n2. modprobe null_blk nr_devices=0 submit_queues=8\n3. mkdir /mnt/nullb/nullb0\n4. echo 1 > /mnt/nullb/nullb0/power\n5. echo 4 > /mnt/nullb/nullb0/submit_queues\n6. rmdir /mnt/nullb/nullb0\n\nIn step 4, will alloc 9 tags (8 submit queues and 1 poll queue), then\nin step 5, new_nr_hw_queues = 5 (4 submit queues and 1 poll queue).\nAt last in step 6, only these 5 tags are freed, the other 4 tags leaked."
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                        "baseScore": 7.5,
                        "baseSeverity": "HIGH"
                    },
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "AV:N - The shrink is driven by remote-peer data on NVMe-oF hosts — `nvme_set_queue_count()` takes the I/O queue count verbatim from the target's Set Features completion and feeds it to `blk_mq_update_nr_hw_queues()` on every reconnect, with the tag set persisting across reconnects. A hostile/compromised target or on-path attacker on an unauthenticated NVMe/TCP fabric reaches the vulnerable code over the network.\nAC:L - The attacker fully controls the granted queue count in each Set Features response and can force reconnects at will by closing the transport connection, so each shrink→grow cycle is triggered deterministically with no conditions outside the attacker's control.\nPR:N - The remote peer needs no credentials on the victim host; NVMe/TCP in the affected 5.16–6.5 range has no in-band authentication or TLS, and the queue-count negotiation happens automatically during controller reconnect.\nUI:N - Reconnect and queue renegotiation are fully automatic in the nvme fabrics keep-alive/reconnect path; no administrator or user action is needed at exploitation time.\nS:U - The leaked allocations and the resulting memory pressure are confined to the kernel of the affected host; no security authority boundary such as a VM or IOMMU domain is crossed.\nC:N - The leaked `blk_mq_tags` and request pages are simply never freed — they are not read, exposed, or transmitted anywhere, so no information is disclosed to the attacker.\nI:N - No out-of-bounds write, use-after-free, or type confusion occurs; the stale pointers are only dropped, leaving no primitive to modify kernel or user data.\nA:H - Because the regrow path memcpy's only the shrunken count and frees the old array, every shrink→grow cycle permanently leaks a full per-queue request pool, making the leak unbounded and repeatable until kernel memory is exhausted and the system OOMs or hangs."
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "block/blk-mq.c"
                    ],
                    "versions": [
                        {
                            "version": "a846a8e6c9a5949582c5a6a8bbc83a7d27fd891e",
                            "lessThan": "c0ef7493e68b8896806a2f598fcffbaa97333405",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "a846a8e6c9a5949582c5a6a8bbc83a7d27fd891e",
                            "lessThan": "e1dd7bc93029024af5688253b0c05181d6e01f8e",
                            "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/blk-mq.c"
                    ],
                    "versions": [
                        {
                            "version": "5.16",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "5.16",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.5.5",
                            "lessThanOrEqual": "6.5.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6",
                            "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": "5.16",
                                    "versionEndExcluding": "6.5.5"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.16",
                                    "versionEndExcluding": "6.6"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/c0ef7493e68b8896806a2f598fcffbaa97333405"
                },
                {
                    "url": "https://git.kernel.org/stable/c/e1dd7bc93029024af5688253b0c05181d6e01f8e"
                }
            ],
            "title": "blk-mq: fix tags leak when shrink nr_hw_queues",
            "x_generator": {
                "engine": "bippy-1.2.0"
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    }
}