---
id: CVE-2024-36899
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  gpiolib: cdev: Fix use after free in lineinfo_changed_notify

  The use-after-free issue occurs as follows: when the GPIO chip device file
  is being closed by invoking gpi…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  gpiolib: cdev: Fix use after free in lineinfo_changed_notify

  The use-after-free issue occurs as follows: when the GPIO chip device file
  is being closed by invoking gpi…
severity: high
cvss: 7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-362
  - CWE-416
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 5.7, < 6.6.31'
  - 'linux_kernel >= 6.7, < 6.8.10'
  - linux_kernel = 6.9
patched:
  - linux_kernel 6.8.10
published: '2024-05-30'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T01:18:23.673'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2024-36899'
references:
  - url: 'https://git.kernel.org/stable/c/02f6b0e1ec7e0e7d059dddc893645816552039da'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2d008d4961b039d2edce8976289773961b7e5fb5'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2dfbb920a89bdc58087672ad5325dc6c588b6860'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/95ca7c90eaf5ea8a8460536535101e3e81160e2a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ca710b5f40b8b16fdcad50bebd47f50e4c62d239'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d38c49f7bdf14381270736299e2ff68ec248a017'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/02f6b0e1ec7e0e7d059dddc893645816552039da'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://git.kernel.org/stable/c/95ca7c90eaf5ea8a8460536535101e3e81160e2a'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://git.kernel.org/stable/c/ca710b5f40b8b16fdcad50bebd47f50e4c62d239'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-265688.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00178
epssPercentile: 0.07268
ingestedAt: '2026-10-15T03:30:12.699Z'
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2024-06-10T18:48:31.477532Z'
---

## Overview

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

gpiolib: cdev: Fix use after free in lineinfo_changed_notify

The use-after-free issue occurs as follows: when the GPIO chip device file
is being closed by invoking gpio_chrdev_release(), watched_lines is freed
by bitmap_free(), but the unregistration of lineinfo_changed_nb notifier
chain failed due to waiting write rwsem. Additionally, one of the GPIO
chip's lines is also in the release process and holds the notifier chain's
read rwsem. Consequently, a race condition leads to the use-after-free of
watched_lines.

Here is the typical stack when issue happened:

[free]
gpio_chrdev_release()
  --> bitmap_free(cdev->watched_lines)                  <-- freed
  --> blocking_notifier_chain_unregister()
    --> down_write(&nh->rwsem)                          <-- waiting rwsem
          --> __down_write_common()
            --> rwsem_down_write_slowpath()
                  --> schedule_preempt_disabled()
                    --> schedule()

[use]
st54spi_gpio_dev_release()
  --> gpio_free()
    --> gpiod_free()
      --> gpiod_free_commit()
        --> gpiod_line_state_notify()
          --> blocking_notifier_call_chain()
            --> down_read(&nh->rwsem);                  <-- held rwsem
            --> notifier_call_chain()
              --> lineinfo_changed_notify()
                --> test_bit(xxxx, cdev->watched_lines) <-- use after free

The side effect of the use-after-free issue is that a GPIO line event is
being generated for userspace where it shouldn't. However, since the chrdev
is being closed, userspace won't have the chance to read that event anyway.

To fix the issue, call the bitmap_free() function after the unregistration
of lineinfo_changed_nb notifier chain.

## Affected

- `linux_kernel >= 5.7, < 6.6.31`
- `linux_kernel >= 6.7, < 6.8.10`
- `linux_kernel = 6.9`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.8.10`