---
id: CVE-2026-98972
title: 'cgroup/cpuset: Don''t access cpuset_cgrp_subsys.root in is_in_v2_mode()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  cgroup/cpuset: Don't access cpuset_cgrp_subsys.root in is_in_v2_mode()

  After seeing the patch [1] to guard is_in_v2_mode() with RCU, it makes
  me realize that is_in_v2_…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= b8d1b8ee93df8ffbabbeadd65d39853cfad6d698 <
    988bf67a13890a37a33201f95947095ca9bec856
  - >-
    Linux >= b8d1b8ee93df8ffbabbeadd65d39853cfad6d698 <
    e06b678e3b4e12fdaa0b51a7a5a54abc5dbd6469
  - Linux 4.14
published: '2026-10-23'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T12:19:45.458Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98972'
references:
  - url: 'https://git.kernel.org/stable/c/988bf67a13890a37a33201f95947095ca9bec856'
  - url: 'https://git.kernel.org/stable/c/e06b678e3b4e12fdaa0b51a7a5a54abc5dbd6469'
tags:
  - cve.org
ingestedAt: '2026-10-23T13:24:55.552Z'
---

## Overview

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

cgroup/cpuset: Don't access cpuset_cgrp_subsys.root in is_in_v2_mode()

After seeing the patch [1] to guard is_in_v2_mode() with RCU, it makes
me realize that is_in_v2_mode() may be called in a context where a new
cgroup filesystem is being rebound with stale cpuset_cgrp_subsys.root
pointer. Avoid this potential UaF situation by adding a new cpuset_v2_mode
flag which is set when the cpuset_v2_mode mount option is used. This
flag is written into only when cpuset_bind() is being called with a
stable cpuset_cgrp_subsys.root value. The is_in_v2_mode() helper is
modified to read the new cpuset_v2_mode flag instead of accessing
cpuset_cgrp_subsys.root directly.

[1] https://lore.kernel.org/lkml/20260929084124.626693-2-arighi@nvidia.com

## Affected

- `Linux >= b8d1b8ee93df8ffbabbeadd65d39853cfad6d698 < 988bf67a13890a37a33201f95947095ca9bec856`
- `Linux >= b8d1b8ee93df8ffbabbeadd65d39853cfad6d698 < e06b678e3b4e12fdaa0b51a7a5a54abc5dbd6469`
- `Linux 4.14`

## Remediation

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