---
id: CVE-2026-98013
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/sched: fq_pie: clamp quantum in change path

  fq_pie_change() accepts any quantum value from userspace, including 1.
  With a crafted size table qdisc_pkt_len reaches …
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/sched: fq_pie: clamp quantum in change path

  fq_pie_change() accepts any quantum value from userspace, including 1.
  With a crafted size table qdisc_pkt_len reaches …
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= ec97ecf1ebe485a17cd8395a5f35e6b80b57665a <
    f90fe65b977e7aa9eb302230a09eb18f8c32ceaa
  - >-
    Linux >= ec97ecf1ebe485a17cd8395a5f35e6b80b57665a <
    c11e3a39807eb5a200445ae9082843ab86800415
  - >-
    Linux >= ec97ecf1ebe485a17cd8395a5f35e6b80b57665a <
    6655b56e2801008566c594ef231f6c7b3f716c61
  - >-
    Linux >= ec97ecf1ebe485a17cd8395a5f35e6b80b57665a <
    4864f58c53eb47257d55e01f47d4a9f355f7f970
  - Linux 5.6
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T11:17:29.660'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98013'
references:
  - url: 'https://git.kernel.org/stable/c/4864f58c53eb47257d55e01f47d4a9f355f7f970'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6655b56e2801008566c594ef231f6c7b3f716c61'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c11e3a39807eb5a200445ae9082843ab86800415'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f90fe65b977e7aa9eb302230a09eb18f8c32ceaa'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-25T11:06:38.858Z'
---

## Overview

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

net/sched: fq_pie: clamp quantum in change path

fq_pie_change() accepts any quantum value 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, ...) matching fq_codel_change().

Conditions to recreate the bug:
  CONFIG_NET_SCH_FQ_PIE=y. Requires CAP_NET_ADMIN (namespace-local via
  unshare -Urn suffices).

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

## Remediation

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