---
id: CVE-2026-98009
title: |-
  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
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 cra…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <
    99ae477b892e203a37985ebc56f0063e072f7f4b
  - >-
    Linux >= dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <
    8f80b113dea0bed3c1a31a4224b72775cd9ec52d
  - >-
    Linux >= dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <
    de22c30ec5598aca8797f02082d2ee1358dfa3ff
  - >-
    Linux >= dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <
    1c38487f46b243bfeefec0c0c86023a3904f2214
  - Linux 5.6
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T11:17:29.210'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98009'
references:
  - url: 'https://git.kernel.org/stable/c/1c38487f46b243bfeefec0c0c86023a3904f2214'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8f80b113dea0bed3c1a31a4224b72775cd9ec52d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/99ae477b892e203a37985ebc56f0063e072f7f4b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/de22c30ec5598aca8797f02082d2ee1358dfa3ff'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-25T11:06:38.859Z'
---

## Overview

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

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.