---
id: CVE-2026-90066
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify

  ftrace_direct_multi_init() assigns kthread_run()'s return value to
  simple_tsk without an IS…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify

  ftrace_direct_multi_init() assigns kthread_run()'s return value to
  simple_tsk without an IS…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= e1067a07cfbc5a36abad3752fafe4c79e06db1bb <
    7a96b9f6d5ba23dbce66c8a4a242effd4c01a830
  - >-
    Linux >= e1067a07cfbc5a36abad3752fafe4c79e06db1bb <
    98b7b2a29ae87937aa02ab9391543ef8c602cd94
  - >-
    Linux >= e1067a07cfbc5a36abad3752fafe4c79e06db1bb <
    626614df9080d7052fbe24dc90b5434717ab7a9f
  - >-
    Linux >= e1067a07cfbc5a36abad3752fafe4c79e06db1bb <
    cf839636911d8313f3ecd098329fd0b96499e4cf
  - >-
    Linux >= e1067a07cfbc5a36abad3752fafe4c79e06db1bb <
    6727b7618f49401acf373fa3ec5712e2ec52e5cf
  - Linux 5.16
published: '2026-09-17'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T17:16:55.437'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90066'
references:
  - url: 'https://git.kernel.org/stable/c/626614df9080d7052fbe24dc90b5434717ab7a9f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6727b7618f49401acf373fa3ec5712e2ec52e5cf'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7a96b9f6d5ba23dbce66c8a4a242effd4c01a830'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/98b7b2a29ae87937aa02ab9391543ef8c602cd94'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cf839636911d8313f3ecd098329fd0b96499e4cf'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-17T16:21:47.900Z'
epss: 0.002
epssPercentile: 0.08725
---

## Overview

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

samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify

ftrace_direct_multi_init() assigns kthread_run()'s return value to
simple_tsk without an IS_ERR() check. When kthread_run() fails it
returns ERR_PTR(-ENOMEM), but init still returns 0, so the module loads
with simple_tsk holding an error pointer. On unload,
ftrace_direct_multi_exit() then passes that ERR_PTR to kthread_stop(),
leading to a null-pointer-dereference.

Check the return value of kthread_run() with IS_ERR(); on failure,
unregister the ftrace direct call and propagate the error code.

## Remediation

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