---
id: CVE-2025-39691
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  fs/buffer: fix use-after-free when call bh_read() helper

  There's issue as follows:
  BUG: KASAN: stack-out-of-bounds in end_buffer_read_sync+0xe3/0x110
  Read of size 8 at…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  fs/buffer: fix use-after-free when call bh_read() helper

  There's issue as follows:
  BUG: KASAN: stack-out-of-bounds in end_buffer_read_sync+0xe3/0x110
  Read of size 8 at…
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-416
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 2.6.13, < 5.4.297'
  - 'linux_kernel >= 5.5, < 5.10.241'
  - 'linux_kernel >= 5.11, < 5.15.190'
  - 'linux_kernel >= 5.16, < 6.1.149'
  - 'linux_kernel >= 6.2, < 6.6.103'
  - 'linux_kernel >= 6.7, < 6.12.44'
  - 'linux_kernel >= 6.13, < 6.16.4'
  - linux_kernel = 2.6.12
  - linux_kernel = 6.17
  - debian_linux = 11.0
patched:
  - linux_kernel 6.16.4
published: '2025-09-05'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T02:17:59.057'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-39691'
references:
  - url: 'https://git.kernel.org/stable/c/03b40bf5d0389ca23ae6857ee25789f0e0b47ce8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/042cf48ecf67f72c8b3846c7fac678f472712ff3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/3169edb8945c295cf89120fc6b2c35cfe3ad4c9e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/70a09115da586bf662c3bae9c0c4a1b99251fad9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7375f22495e7cd1c5b3b5af9dcc4f6dffe34ce49'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/90b5193edb323fefbee0e4e5bc39ed89dcc37719'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c58c6b532b7b69537cfd9ef701c7e37cdcf79dc4'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c5aa6ba1127307ab5dc3773eaf40d73a3423841f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-019113.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-032379.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-457936.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00186
epssPercentile: 0.08139
ingestedAt: '2026-09-08T15:33:26.997Z'
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-15T21:53:28.798448Z'
---

## Overview

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

fs/buffer: fix use-after-free when call bh_read() helper

There's issue as follows:
BUG: KASAN: stack-out-of-bounds in end_buffer_read_sync+0xe3/0x110
Read of size 8 at addr ffffc9000168f7f8 by task swapper/3/0
CPU: 3 UID: 0 PID: 0 Comm: swapper/3 Not tainted 6.16.0-862.14.0.6.x86_64
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
Call Trace:
 <IRQ>
 dump_stack_lvl+0x55/0x70
 print_address_description.constprop.0+0x2c/0x390
 print_report+0xb4/0x270
 kasan_report+0xb8/0xf0
 end_buffer_read_sync+0xe3/0x110
 end_bio_bh_io_sync+0x56/0x80
 blk_update_request+0x30a/0x720
 scsi_end_request+0x51/0x2b0
 scsi_io_completion+0xe3/0x480
 ? scsi_device_unbusy+0x11e/0x160
 blk_complete_reqs+0x7b/0x90
 handle_softirqs+0xef/0x370
 irq_exit_rcu+0xa5/0xd0
 sysvec_apic_timer_interrupt+0x6e/0x90
 </IRQ>

 Above issue happens when do ntfs3 filesystem mount, issue may happens
 as follows:
           mount                            IRQ
ntfs_fill_super
  read_cache_page
    do_read_cache_folio
      filemap_read_folio
        mpage_read_folio
	 do_mpage_readpage
	  ntfs_get_block_vbo
	   bh_read
	     submit_bh
	     wait_on_buffer(bh);
	                            blk_complete_reqs
				     scsi_io_completion
				      scsi_end_request
				       blk_update_request
				        end_bio_bh_io_sync
					 end_buffer_read_sync
					  __end_buffer_read_notouch
					   unlock_buffer

            wait_on_buffer(bh);--> return will return to caller

					  put_bh
					    --> trigger stack-out-of-bounds
In the mpage_read_folio() function, the stack variable 'map_bh' is
passed to ntfs_get_block_vbo(). Once unlock_buffer() unlocks and
wait_on_buffer() returns to continue processing, the stack variable
is likely to be reclaimed. Consequently, during the end_buffer_read_sync()
process, calling put_bh() may result in stack overrun.

If the bh is not allocated on the stack, it belongs to a folio.  Freeing
a buffer head which belongs to a folio is done by drop_buffers() which
will fail to free buffers which are still locked.  So it is safe to call
put_bh() before __end_buffer_read_notouch().

## Affected

- `linux_kernel >= 2.6.13, < 5.4.297`
- `linux_kernel >= 5.5, < 5.10.241`
- `linux_kernel >= 5.11, < 5.15.190`
- `linux_kernel >= 5.16, < 6.1.149`
- `linux_kernel >= 6.2, < 6.6.103`
- `linux_kernel >= 6.7, < 6.12.44`
- `linux_kernel >= 6.13, < 6.16.4`
- `linux_kernel = 2.6.12`
- `linux_kernel = 6.17`
- `debian_linux = 11.0`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.16.4`