---
id: CVE-2026-89771
title: >-
  kernel: ring-buffer: Fix subbuf resize race with ring buffer readers
  (CVE-2026-89771)
summary: >-
  A flaw was found in the Linux kernel. A race condition exists in the ring
  buffer resizing mechanism, where `trace_buffer subbuf_size` can be read
  without proper locking while it is being simultaneously resized. This could
  allow a local att…
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-366
vendor: Red Hat
product: Red Hat Enterprise Linux 10
affected:
  - enterprise_linux 10
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-15'
sourceUpdated: '2026-09-15T19:23:24+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89771.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89771.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89771'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532138'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89771'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89771'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89771.mbox
  - url: 'https://git.kernel.org/stable/c/0c7c517827a453128a8f58bfd849546a29813b27'
  - url: 'https://git.kernel.org/stable/c/50f4a793c4ff24826efb0ac700989a5063cc53df'
  - url: 'https://git.kernel.org/stable/c/6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9'
  - url: 'https://git.kernel.org/stable/c/8a5f63637890f03177146efddaba5ec7a1b4d61f'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.0012
epssPercentile: 0.02064
scores:
  vendor: 4.7
  cna: 7.8
ingestedAt: '2026-09-14T15:23:07.472Z'
---

## Overview

A flaw was found in the Linux kernel. A race condition exists in the ring buffer resizing mechanism, where `trace_buffer subbuf_size` can be read without proper locking while it is being simultaneously resized. This could allow a local attacker to trigger unpredictable behavior or a denial of service (DoS) by causing system instability.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat OpenShift Container Platform 4 · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89771.json)

**kernel: ring-buffer: Fix subbuf resize race with ring buffer readers** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-15.

Affected:

- Red Hat Enterprise Linux 10
- Red Hat OpenShift Container Platform 4

No fix planned:

- Red Hat Enterprise Linux 10
- Red Hat OpenShift Container Platform 4

Not affected:

- 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

## Remediation

Fix deferred