---
id: CVE-2026-89503
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page()

  ring_buffer_alloc_read_page() is racy with ring_buffer_subbuf_order_set,
  it can allocate a reade…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page()

  ring_buffer_alloc_read_page() is racy with ring_buffer_subbuf_order_set,
  it can allocate a reade…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-367
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= bce761d757452ba5eb77e11fecc37a04b67494e7 <
    2313ff69bd237aad264a5913907f374f958335a2
  - >-
    Linux >= bce761d757452ba5eb77e11fecc37a04b67494e7 <
    2dc510957fe8fd098ab3c3147ebdf34d00cd2734
  - >-
    Linux >= bce761d757452ba5eb77e11fecc37a04b67494e7 <
    53106e9262a310ef2c9a9321168c03705940c678
  - >-
    Linux >= bce761d757452ba5eb77e11fecc37a04b67494e7 <
    e743527c5bfdceda1095bc0a9e596e2aebb6a9c3
  - Linux 6.8
published: '2026-09-11'
updated: '2026-10-03'
sourceUpdated: '2026-10-03T11:17:42.583'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89503'
references:
  - url: 'https://git.kernel.org/stable/c/2313ff69bd237aad264a5913907f374f958335a2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2dc510957fe8fd098ab3c3147ebdf34d00cd2734'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/53106e9262a310ef2c9a9321168c03705940c678'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e743527c5bfdceda1095bc0a9e596e2aebb6a9c3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89503.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89503'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532017'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89503'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89503'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89503.mbox
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00168
epssPercentile: 0.06064
scores:
  nvd: 7.8
  vendor: 5.5
  cna: 7.8
ingestedAt: '2026-09-14T15:23:07.475Z'
---

## Overview

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

ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page()

ring_buffer_alloc_read_page() is racy with ring_buffer_subbuf_order_set,
it can allocate a reader page with an outdated order. This isn't a big
issue, the user can still re-allocate a new reader page and try again.

However, what is more problematic is if the value of subbuf_order
changes in the middle of ring_buffer_alloc_read_page(). In that case,
bpage->order might not match the actual allocated memory.

Use bpage->order for the allocation to prevent this race.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10 · no fix planned: Red Hat Enterprise Linux 10 · updated 2026-10-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89503.json)