---
id: CVE-2026-89745
title: 'debugfs: Fix lockdown check for mmap_prepare'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  debugfs: Fix lockdown check for mmap_prepare

  Commit 651fdda8406d ("relay: update relay to use mmap_prepare")
  changed the `mmap` file operation to `mmap_prepare` for re…
severity: high
cvss: 7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: vendor
cwe:
  - CWE-414
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 651fdda8406d42a5004c5c79f269540a85d6a1ab <
    e7f6a6b5741d16fdac7adaecbe0fa52ae756f208
  - >-
    Linux >= 651fdda8406d42a5004c5c79f269540a85d6a1ab <
    f81808de37338aac8e167f99bfae647b1b835c70
  - Linux 6.19
published: '2026-09-11'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:51:59.176Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89745'
references:
  - url: 'https://git.kernel.org/stable/c/e7f6a6b5741d16fdac7adaecbe0fa52ae756f208'
  - url: 'https://git.kernel.org/stable/c/f81808de37338aac8e167f99bfae647b1b835c70'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89745.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89745'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532369'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89745'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89745'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89745.mbox
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00198
epssPercentile: 0.09443
ingestedAt: '2026-09-14T11:11:19.884Z'
---

## Overview

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

debugfs: Fix lockdown check for mmap_prepare

Commit 651fdda8406d ("relay: update relay to use mmap_prepare")
changed the `mmap` file operation to `mmap_prepare` for relayfs, but
the lockdown check in debugfs was not updated accordingly.

This prevents debugfs from being locked down when the kernel is in
integrity mode if a file uses `mmap_prepare` but not `mmap`.

Since the conversion to `mmap_prepare` across the kernel is not yet
complete, update the lockdown check to look for both `mmap` and
`mmap_prepare` to ensure comprehensive coverage.

## Affected

- `Linux >= 651fdda8406d42a5004c5c79f269540a85d6a1ab < e7f6a6b5741d16fdac7adaecbe0fa52ae756f208`
- `Linux >= 651fdda8406d42a5004c5c79f269540a85d6a1ab < f81808de37338aac8e167f99bfae647b1b835c70`
- `Linux 6.19`

## 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 6 · no fix planned: Red Hat Enterprise Linux 6 · updated 2026-09-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89745.json)