---
id: CVE-2026-23002
title: 'lib/buildid: use __kernel_read() for sleepable context'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  lib/buildid: use __kernel_read() for sleepable context

  Prevent a "BUG: unable to handle kernel NULL pointer dereference in
  filemap_read_folio".

  For the sleepable cont…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= ad41251c290dfe3c01472c94d2439a59de23fe97 <
    b11dfb7708f212b96c7973a474014c071aa02e05
  - >-
    Linux >= ad41251c290dfe3c01472c94d2439a59de23fe97 <
    568aeb3476c770a3863c755dd2a199c212434286
  - >-
    Linux >= ad41251c290dfe3c01472c94d2439a59de23fe97 <
    777a8560fd29738350c5094d4166fe5499452409
  - Linux 6.12
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-05T21:18:20.306589Z'
exploitAvailable: true
published: '2026-01-25'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T21:23:14.922Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-23002'
references:
  - url: 'https://git.kernel.org/stable/c/b11dfb7708f212b96c7973a474014c071aa02e05'
  - url: 'https://git.kernel.org/stable/c/568aeb3476c770a3863c755dd2a199c212434286'
  - url: 'https://git.kernel.org/stable/c/777a8560fd29738350c5094d4166fe5499452409'
tags:
  - cve.org
  - exploit-available
epss: 0.00176
epssPercentile: 0.07188
exploits:
  github: 1
  githubRepos:
    - >-
      https://github.com/George0Papasotiriou/CVE-2026-23002-5G-NAS-Message-Buffer-Overflow-in-gNodeB
  checkedAt: '2026-11-08T19:17:29.716Z'
ingestedAt: '2026-11-05T22:38:32.062Z'
---

## Overview

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

lib/buildid: use __kernel_read() for sleepable context

Prevent a "BUG: unable to handle kernel NULL pointer dereference in
filemap_read_folio".

For the sleepable context, convert freader to use __kernel_read() instead
of direct page cache access via read_cache_folio().  This simplifies the
faultable code path by using the standard kernel file reading interface
which handles all the complexity of reading file data.

At the moment we are not changing the code for non-sleepable context which
uses filemap_get_folio() and only succeeds if the target folios are
already in memory and up-to-date.  The reason is to keep the patch simple
and easier to backport to stable kernels.

Syzbot repro does not crash the kernel anymore and the selftests run
successfully.

In the follow up we will make __kernel_read() with IOCB_NOWAIT work for
non-sleepable contexts.  In addition, I would like to replace the
secretmem check with a more generic approach and will add fstest for the
buildid code.

## Affected

- `Linux >= ad41251c290dfe3c01472c94d2439a59de23fe97 < b11dfb7708f212b96c7973a474014c071aa02e05`
- `Linux >= ad41251c290dfe3c01472c94d2439a59de23fe97 < 568aeb3476c770a3863c755dd2a199c212434286`
- `Linux >= ad41251c290dfe3c01472c94d2439a59de23fe97 < 777a8560fd29738350c5094d4166fe5499452409`
- `Linux 6.12`

## Remediation

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