---
id: CVE-2026-98610
title: >-
  kernel: net/sched: sch_hfsc: bound the classify inner-filter walk with a drift
  budget (CVE-2026-98610)
summary: >-
  A flaw was found in the Linux kernel's Hierarchical Fair Service Curve (HFSC)
  network packet scheduler. A local user with network administration privileges,
  such as within a user namespace, can exploit this flaw to cause a Denial of
  Servic…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: vendor
cwe: CWE-835
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 6
  - enterprise_linux 7
  - enterprise_linux 8
  - enterprise_linux 9
  - openshift_container_platform 4
published: '2026-10-18'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T07:49:36+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98610.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98610.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-98610'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2555036'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-98610'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98610'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98610.mbox
  - url: 'https://git.kernel.org/stable/c/d4fd251e3311727c32af89344d3332f788c153a2'
  - url: 'https://git.kernel.org/stable/c/30d7fea767e830bd81ac2f73d2e33c877cb2e679'
  - url: 'https://git.kernel.org/stable/c/f476fb656ca2326d7b2eba98d03ced1cbcf5cd99'
  - url: 'https://git.kernel.org/stable/c/e8f9979286f70dfbfe0552e2a63000950841bea6'
  - url: 'https://git.kernel.org/stable/c/2bd20245dd658789d8cccb37697967b4caba6ad8'
  - url: 'https://git.kernel.org/stable/c/0fa25ba50a382d79c0cf060214c2095756836f5f'
  - url: 'https://git.kernel.org/stable/c/1301a1292c6742b4c96a18715d49f89c3caca0d7'
  - url: 'https://git.kernel.org/stable/c/8a60ade2277e1f0e0d0578d565354e52292fa46d'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00216
epssPercentile: 0.12004
ingestedAt: '2026-10-18T15:45:12.242Z'
---

## Overview

A flaw was found in the Linux kernel's Hierarchical Fair Service Curve (HFSC) network packet scheduler. A local user with network administration privileges, such as within a user namespace, can exploit this flaw to cause a Denial of Service (DoS). Due to a lack of revalidation when traffic class levels are adjusted, conflicting filter configurations can create an infinite loop during packet classification. When network traffic traverses these cyclic rules, the system becomes unresponsive or crashes.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-10-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98610.json)

**kernel: net/sched: sch_hfsc: bound the classify inner-filter walk with a drift budget** — rated Moderate by Red Hat. Released 2026-10-18, updated 2026-10-21.

Affected:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

No fix planned:

- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

## Remediation

Out of support scope