FKIE_CVE-2026-98009

Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-09-25 11:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: net/sched: ets: clamp quantum in parse and fallback paths ets_qdisc_change() falls back to psched_mtu() with no floor for bands without an explicit quantum. With a crafted size table qdisc_pkt_len reaches ~2 GiB, so a zero psched_mtu on a headerless device makes the deficit-refill loop spin under the qdisc lock. Move the floor into ets_quantum_parse() so explicitly configured quanta are also clamped to [256, 1<<20], not just the fallback path. Conditions to recreate the bug: CONFIG_NET_SCH_ETS=y. Requires CAP_NET_ADMIN (namespace-local via unshare -Urn suffices). tc qdisc add dev dummy0 root ets bands 3 strict 2 quanta 1 1
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1c38487f46b243bfeefec0c0c86023a3904f2214
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8f80b113dea0bed3c1a31a4224b72775cd9ec52d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/99ae477b892e203a37985ebc56f0063e072f7f4b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/de22c30ec5598aca8797f02082d2ee1358dfa3ff
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sched/sch_ets.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "99ae477b892e203a37985ebc56f0063e072f7f4b",
              "status": "affected",
              "version": "dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33",
              "versionType": "git"
            },
            {
              "lessThan": "8f80b113dea0bed3c1a31a4224b72775cd9ec52d",
              "status": "affected",
              "version": "dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33",
              "versionType": "git"
            },
            {
              "lessThan": "de22c30ec5598aca8797f02082d2ee1358dfa3ff",
              "status": "affected",
              "version": "dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33",
              "versionType": "git"
            },
            {
              "lessThan": "1c38487f46b243bfeefec0c0c86023a3904f2214",
              "status": "affected",
              "version": "dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/sched/sch_ets.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.6"
            },
            {
              "lessThan": "5.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: ets: clamp quantum in parse and fallback paths\n\nets_qdisc_change() falls back to psched_mtu() with no floor for bands\nwithout an explicit quantum. With a crafted size table qdisc_pkt_len\nreaches ~2 GiB, so a zero psched_mtu on a headerless device makes the\ndeficit-refill loop spin under the qdisc lock.\n\nMove the floor into ets_quantum_parse() so explicitly configured quanta\nare also clamped to [256, 1\u003c\u003c20], not just the fallback path.\n\nConditions to recreate the bug:\n  CONFIG_NET_SCH_ETS=y. Requires CAP_NET_ADMIN (namespace-local via\n  unshare -Urn suffices).\n\n  tc qdisc add dev dummy0 root ets bands 3 strict 2 quanta 1 1"
    }
  ],
  "id": "CVE-2026-98009",
  "lastModified": "2026-09-25T11:17:29.210",
  "metrics": {},
  "published": "2026-09-25T11:17:29.210",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1c38487f46b243bfeefec0c0c86023a3904f2214"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8f80b113dea0bed3c1a31a4224b72775cd9ec52d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/99ae477b892e203a37985ebc56f0063e072f7f4b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/de22c30ec5598aca8797f02082d2ee1358dfa3ff"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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