---
id: CVE-2026-90074
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/sched: fq_pie: clamp default quantum to avoid signed overflow

  fq_pie_init() sets q->quantum = psched_mtu(qdisc_dev(sch)) without
  clamping
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/sched: fq_pie: clamp default quantum to avoid signed overflow

  fq_pie_init() sets q->quantum = psched_mtu(qdisc_dev(sch)) without
  clamping. A device with a huge MTU…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= ec97ecf1ebe485a17cd8395a5f35e6b80b57665a <
    1f43e4dbc93b7d02761a024d5f895df823c07b72
  - >-
    Linux >= ec97ecf1ebe485a17cd8395a5f35e6b80b57665a <
    f7942b2693bc24c7d609a03d06f97bee3b0bd96a
  - >-
    Linux >= ec97ecf1ebe485a17cd8395a5f35e6b80b57665a <
    6f1be05faecef4c0f9a008200209f66ef2e133f7
  - >-
    Linux >= ec97ecf1ebe485a17cd8395a5f35e6b80b57665a <
    435da3734a8e63d3067016accc977ed1d10aaaa0
  - >-
    Linux >= ec97ecf1ebe485a17cd8395a5f35e6b80b57665a <
    44dad8fe99b58a7fe2961e9eec6a5f07ace5b51f
  - >-
    Linux >= ec97ecf1ebe485a17cd8395a5f35e6b80b57665a <
    044fa2498bbc2900f0c48a6ef2fdd5b2bdfc3795
  - >-
    Linux >= ec97ecf1ebe485a17cd8395a5f35e6b80b57665a <
    bf97fd2163ad1191ef8daa3d4df8372aee19e396
  - >-
    Linux >= ec97ecf1ebe485a17cd8395a5f35e6b80b57665a <
    c86cd7ed0b0e44779a3d1683f03e4353baf4bdc9
  - Linux 5.6
published: '2026-09-17'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T17:16:56.530'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90074'
references:
  - url: 'https://git.kernel.org/stable/c/044fa2498bbc2900f0c48a6ef2fdd5b2bdfc3795'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/1f43e4dbc93b7d02761a024d5f895df823c07b72'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/435da3734a8e63d3067016accc977ed1d10aaaa0'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/44dad8fe99b58a7fe2961e9eec6a5f07ace5b51f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6f1be05faecef4c0f9a008200209f66ef2e133f7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/bf97fd2163ad1191ef8daa3d4df8372aee19e396'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c86cd7ed0b0e44779a3d1683f03e4353baf4bdc9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f7942b2693bc24c7d609a03d06f97bee3b0bd96a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-17T16:21:47.898Z'
epss: 0.0021
epssPercentile: 0.10011
---

## Overview

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

net/sched: fq_pie: clamp default quantum to avoid signed overflow

fq_pie_init() sets q->quantum = psched_mtu(qdisc_dev(sch)) without
clamping. A device with a huge MTU (e.g. dummy with max_mtu == 0
accepting MTU 2147483634) makes psched_mtu() return 0x80000000, which
overflows the signed flow->deficit to INT_MIN in fq_pie_qdisc_dequeue(),
causing an infinite loop and soft lockup. Emulate fq_pie_policy which
is already bounded to [1, 1 << 20]; clamp the default to [256, 1 << 20].
256 matches fq_codel's floor and is a sane minimum for a DRR quantum.

Conditions to recreate the bug: a device whose MTU (plus
hard_header_len) wraps psched_mtu() into the sign bit (e.g. a dummy
device with max_mtu == 0 accepting MTU 2147483634). Requires
CAP_NET_ADMIN in a user namespace.

## Remediation

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