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CVE-2026-90050

Estado: RecibidaSin puntuar—

In the Linux kernel, the following vulnerability has been resolved:

net/sched: fq: clamp quantum and initial_quantum in change path

The fq change path accepts TCA_FQ_QUANTUM in [1, INT_MAX] and TCA_FQ_INITIAL_QUANTUM up to INT_MAX, while fq_init() already clamps to [1, 1<<20]. A user can override the init clamp via tc qdisc change, restoring the small-quantum deficit spin that the init clamp prevents.

Narrow iq_range.max to 1<<20 so TCA_FQ_INITIAL_QUANTUM is rejected at parse time. Clamp TCA_FQ_QUANTUM to [256, 1<<20] in fq_change() and fq_init() quantum to [256, 1<<20] for tiny-MTU devices.

Detalles técnicos trazas, registros y código del informe original
Conditions to recreate the bug:
  CONFIG_NET_SCH_FQ=y. Requires CAP_NET_ADMIN (namespace-local via
  unshare -Urn suffices).

  tc qdisc add dev dummy0 root fq
  tc qdisc change dev dummy0 root fq quantum 1 stab data 32768 size_log 15 cell_log 0

CVSS

NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux KernelAI

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-90050",
  "cveTags": [],
  "metrics": {},
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "d16dac3925be95ad46e986d4b139c9898b6e227f",
              "lessThan": "a27498d34c3f429fb6db3aa609569f8154afa175",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f6b3e3848a5fca63438984acd6d9eceac80814c1",
              "lessThan": "798283cd0fe7ba997f67e5a917f14ab40afa8d9f",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e35acd56f244d94355f9ab237c2ecc8fba5e6f04",
              "lessThan": "72e9387884554f47b03bfd40fb8b2bf52789c68d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "709f34f7c28dc4dd6c40343d101850f11e172312",
              "lessThan": "094cc07f98dfe70a34e2a1923af17fd29b8cf622",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/sched/sch_fq.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.3-rc1"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "7.3-rc1",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc3",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/sched/sch_fq.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-17T17:16:53.363",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/094cc07f98dfe70a34e2a1923af17fd29b8cf622",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/72e9387884554f47b03bfd40fb8b2bf52789c68d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/798283cd0fe7ba997f67e5a917f14ab40afa8d9f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a27498d34c3f429fb6db3aa609569f8154afa175",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: fq: clamp quantum and initial_quantum in change path\n\nThe fq change path accepts TCA_FQ_QUANTUM in [1, INT_MAX] and\nTCA_FQ_INITIAL_QUANTUM up to INT_MAX, while fq_init() already clamps to\n[1, 1<<20]. A user can override the init clamp via tc qdisc change,\nrestoring the small-quantum deficit spin that the init clamp prevents.\n\nNarrow iq_range.max to 1<<20 so TCA_FQ_INITIAL_QUANTUM is rejected at\nparse time. Clamp TCA_FQ_QUANTUM to [256, 1<<20] in fq_change() and\nfq_init() quantum to [256, 1<<20] for tiny-MTU devices.\n\nConditions to recreate the bug:\n  CONFIG_NET_SCH_FQ=y. Requires CAP_NET_ADMIN (namespace-local via\n  unshare -Urn suffices).\n\n  tc qdisc add dev dummy0 root fq\n  tc qdisc change dev dummy0 root fq quantum 1 stab data 32768 size_log 15 cell_log 0"
    }
  ],
  "lastModified": "2026-09-17T17:16:53.363",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}