{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-90076",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-09-11T19:38:34.785Z",
        "datePublished": "2026-09-17T16:05:55.517Z",
        "dateUpdated": "2026-10-21T12:49:41.565Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-10-21T12:49:41.565Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: fq: add overflow bounds to quantum and initial quantum\n\nfq_init() computes quantum = 2 * psched_mtu() and initial_quantum = 10 *\npsched_mtu() with no overflow check. A device with a huge MTU (e.g. dummy\nwith max_mtu == 0 accepting MTU 2147483634) makes psched_mtu() return\n0x80000000; the 2 * and 10 * multiplications wrap to 0 in 32-bit\narithmetic, so q->quantum == 0. Then in fq_dequeue() the credit-refill\nloop adds 0 to f->credit (which stays <= 0) and goto begin loops\nforever under the qdisc lock, creating a soft lockup.\n\nClamp psched_mtu() to [1, 1 << 20] before multiplying so the product\ncannot wrap, then cap the result at 1 << 20, matching the bound already\nenforced on TCA_FQ_QUANTUM in fq_change().\n\nConditions to recreate the bug: a device whose MTU (plus\nhard_header_len) is large enough that 2 * psched_mtu() wraps (e.g. a\ndummy device with max_mtu == 0 accepting MTU 2147483634). Requires\nCAP_NET_ADMIN in a user namespace."
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/sched/sch_fq.c"
                    ],
                    "versions": [
                        {
                            "version": "afe4fd062416b158a8a8538b23adc1930a9b88dc",
                            "lessThan": "fd63409b669f9951f1cc6b02486a5254103800d1",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "afe4fd062416b158a8a8538b23adc1930a9b88dc",
                            "lessThan": "d16dac3925be95ad46e986d4b139c9898b6e227f",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "afe4fd062416b158a8a8538b23adc1930a9b88dc",
                            "lessThan": "f6b3e3848a5fca63438984acd6d9eceac80814c1",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "afe4fd062416b158a8a8538b23adc1930a9b88dc",
                            "lessThan": "e35acd56f244d94355f9ab237c2ecc8fba5e6f04",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "afe4fd062416b158a8a8538b23adc1930a9b88dc",
                            "lessThan": "709f34f7c28dc4dd6c40343d101850f11e172312",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/sched/sch_fq.c"
                    ],
                    "versions": [
                        {
                            "version": "3.12",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "3.12",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.160",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.110",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.52",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2.6",
                            "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": "3.12",
                                    "versionEndExcluding": "6.6.160"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "3.12",
                                    "versionEndExcluding": "6.12.110"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "3.12",
                                    "versionEndExcluding": "6.18.52"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "3.12",
                                    "versionEndExcluding": "7.2.6"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "3.12",
                                    "versionEndExcluding": "7.3"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/fd63409b669f9951f1cc6b02486a5254103800d1"
                },
                {
                    "url": "https://git.kernel.org/stable/c/d16dac3925be95ad46e986d4b139c9898b6e227f"
                },
                {
                    "url": "https://git.kernel.org/stable/c/f6b3e3848a5fca63438984acd6d9eceac80814c1"
                },
                {
                    "url": "https://git.kernel.org/stable/c/e35acd56f244d94355f9ab237c2ecc8fba5e6f04"
                },
                {
                    "url": "https://git.kernel.org/stable/c/709f34f7c28dc4dd6c40343d101850f11e172312"
                }
            ],
            "title": "net/sched: fq: add overflow bounds to quantum and initial quantum",
            "x_generator": {
                "engine": "bippy-1.2.0"
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        }
    }
}