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net/sched: hhf: clamp quantum in change and init paths

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: net/sched: hhf: clamp quantum in change and init paths hhf_change() accepts any quantum from userspace, including 1. With a crafted size table qdisc_pkt_len reaches ~2 GiB, so quantum=1 makes the deficit-refill loop spin ~2^31 times under the qdisc lock (a soft lockup / denial of service). Add max(256U, ...) in hhf_change() matching fq_codel_change(). Clamp hhf_init() to [256, 1<<20] matching the siblings, and remove the old fallback that only set quantum=256 on overflow. Conditions to recreate the bug: CONFIG_NET_SCH_HHF=y. Requires CAP_NET_ADMIN (namespace-local via unshare -Urn suffices). tc qdisc add dev dummy0 root hhf tc qdisc change dev dummy0 root hhf quantum 1 stab data 32768 size_log 15 cell_log 0

Announced Source revision 1
Original source ↗

CVE-2026-98011

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-98011

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "10239edf86f137ce4c39b62ea9575e8053c549a0",
        "lessThan": "a328698d046098e6f55b3b1460cac6bab577be58",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "10239edf86f137ce4c39b62ea9575e8053c549a0",
        "lessThan": "c364ad3ab3c8a6bce469a5cbf02881ab1324c5da",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "10239edf86f137ce4c39b62ea9575e8053c549a0",
        "lessThan": "2c6dd9fc86d446a03728c43f3b96d9ae29aa058f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "10239edf86f137ce4c39b62ea9575e8053c549a0",
        "lessThan": "6570f326a6a96bedf3d1d1dab6acc9f8c29104ec",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "10239edf86f137ce4c39b62ea9575e8053c549a0",
        "lessThan": "1113b674307ffddd402524bd1fd9d7d5629b705b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "10239edf86f137ce4c39b62ea9575e8053c549a0",
        "lessThan": "2e77947bbf6c166e76c038663832d0914418f761",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "10239edf86f137ce4c39b62ea9575e8053c549a0",
        "lessThan": "0898c6f9fa9ce2632ae88bd0f34a878ccc6335af",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "10239edf86f137ce4c39b62ea9575e8053c549a0",
        "lessThan": "eb56a495f59baf6cad5ed80e3ffb9078098b1346",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/sched/sch_hhf.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "3.14"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "3.14",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.271",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.222",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.189",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.158",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.111",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.53",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.7",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/sched/sch_hhf.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98011

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#38138 · Revision 1
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Publisher date
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